diff --git a/CHANGELOG.md b/CHANGELOG.md
index d851101a..f5174dd8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to
 ### Added
 
 - 🔧(backend) settings CONVERSION_UPLOAD_ENABLED to control usage of docspec
+- ✨(backend) add a public_search API view to the Document viewset #2068
 
 ### Changed
 
diff --git a/src/backend/core/api/viewsets.py b/src/backend/core/api/viewsets.py
index 7c27eb15..dbb69c83 100644
--- a/src/backend/core/api/viewsets.py
+++ b/src/backend/core/api/viewsets.py
@@ -512,6 +512,9 @@ class DocumentViewSet(
     15. **AI Proxy**: Proxy an AI request to an external AI service.
         Example: POST /api/v1.0/documents/<resource_id>/ai-proxy
 
+    13. **Public Search**: Search within a public document and the related tree.
+        Example: GET /documents/{id}/public_search/?q=search_text
+
     ### Ordering: created_at, updated_at, is_favorite, title
 
         Example:
@@ -1536,6 +1539,43 @@ class DocumentViewSet(
         queryset = filterset.qs
         return self.get_response_for_queryset(queryset)
 
+    @drf.decorators.action(detail=True, methods=["get"], url_path="public_search")
+    def public_search(self, request, *args, **kwargs):
+        """
+        Returns a DRF response containing the filtered, annotated and ordered document list
+        for public search on the tree of a given public document.
+
+        Applies filtering based on request parameter 'q' from `SearchDocumentSerializer`.
+
+        The filtering is done on the model field 'title', there is no full text search.
+
+        The ordering is always by the most recent first.
+        """
+        document = self.get_object()
+
+        params = serializers.SearchDocumentSerializer(data=request.query_params)
+        params.is_valid(raise_exception=True)
+        text = params.validated_data["q"]
+
+        public_root = document.get_highest_public_ancestor()
+
+        # We limit the queryset to the current public tree, filtering out deleted documents.
+        queryset = public_root.get_descendants(include_self=True).filter(
+            ancestors_deleted_at__isnull=True
+        )
+
+        filterset = DocumentFilter({"title": text}, queryset=queryset)
+
+        if not filterset.is_valid():
+            raise drf.exceptions.ValidationError(filterset.errors)
+
+        queryset = filterset.filter_queryset(queryset)
+        queryset = queryset.filter(ancestors_deleted_at__isnull=True)
+
+        return self.get_response_for_queryset(
+            queryset.order_by("-updated_at"),
+        )
+
     @drf.decorators.action(detail=True, methods=["get"], url_path="versions")
     def versions_list(self, request, *args, **kwargs):
         """
diff --git a/src/backend/core/models.py b/src/backend/core/models.py
index c6ed9ae1..c044e22e 100644
--- a/src/backend/core/models.py
+++ b/src/backend/core/models.py
@@ -1018,6 +1018,22 @@ class Document(MP_Node, BaseModel):
 
         self._content = content
 
+    def get_highest_public_ancestor(self):
+        """
+        Get the highest ancestor of the document that has a public link reach.
+        If the document itself has a public link reach, it will be returned.
+        If there is no public ancestor, None will be returned.
+        """
+        if self.link_reach == LinkReachChoices.PUBLIC:
+            return self
+
+        return (
+            self.get_ancestors()
+            .filter(link_reach=LinkReachChoices.PUBLIC)
+            .order_by("-path")
+            .first()
+        )
+
     def get_content_response(self, version_id=""):
         """Get the content in a specific version of the document"""
         params = {
@@ -1283,6 +1299,8 @@ class Document(MP_Node, BaseModel):
             else (is_owner_or_admin or (user.is_authenticated and self.creator == user))
         ) and not is_deleted
 
+        is_public = link_reach == LinkReachChoices.PUBLIC
+
         ai_allow_reach_from = settings.AI_ALLOW_REACH_FROM
         ai_access = any(
             [
@@ -1319,6 +1337,7 @@ class Document(MP_Node, BaseModel):
             "mask": can_get and user.is_authenticated,
             "move": is_owner_or_admin and not is_deleted,
             "partial_update": can_update,
+            "public_search": is_public and not is_deleted,
             "restore": is_owner,
             "retrieve": retrieve,
             "media_auth": can_get,
diff --git a/src/backend/core/tests/documents/test_api_documents_public_search.py b/src/backend/core/tests/documents/test_api_documents_public_search.py
new file mode 100644
index 00000000..619eed30
--- /dev/null
+++ b/src/backend/core/tests/documents/test_api_documents_public_search.py
@@ -0,0 +1,288 @@
+"""
+Tests for Documents API endpoint: public_search action.
+"""
+
+import datetime
+
+from django.utils import timezone
+
+import pytest
+from rest_framework.test import APIClient
+
+from core import factories, models
+
+pytestmark = pytest.mark.django_db
+
+
+def test_api_documents_public_search_missing_q():
+    """Missing `q` param should return 400."""
+    client = APIClient()
+
+    document = factories.DocumentFactory(link_reach="public")
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={},
+    )
+
+    assert response.status_code == 400
+    assert response.json() == {"q": ["This field is required."]}
+
+
+def test_api_documents_public_search_blank_q():
+    """Blank `q` param should return all documents in the public tree."""
+    client = APIClient()
+    document = factories.DocumentFactory(link_reach="public")
+    child = factories.DocumentFactory(parent=document)
+
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "   "},
+    )
+
+    assert response.status_code == 200
+    result_ids = {r["id"] for r in response.json()["results"]}
+    assert len(result_ids) == 2
+    assert str(document.id) in result_ids
+    assert str(child.id) in result_ids
+
+
+# ---------------------------------------------------------------------------
+# Permissions
+# ---------------------------------------------------------------------------
+
+
+def test_api_documents_public_search_anonymous_on_public_document_tree():
+    """Anonymous users can search within a public document's tree."""
+    client = APIClient()
+
+    document = factories.DocumentFactory(link_reach="public")
+    match = factories.DocumentFactory(parent=document, title="match me")
+    no_match = factories.DocumentFactory(parent=document, title="don't find me")
+
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "match"},
+    )
+    assert response.status_code == 200
+
+    result_ids = {r["id"] for r in response.json()["results"]}
+    assert len(result_ids) == 1
+    assert str(match.id) in result_ids
+    assert str(no_match.id) not in result_ids
+
+
+def test_api_documents_public_search_anonymous_on_restricted_document():
+    """Anonymous users cannot search on a restricted document."""
+    client = APIClient()
+    document = factories.DocumentFactory(link_reach="restricted")
+
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "anything"},
+    )
+    assert response.status_code == 401
+    assert response.json() == {
+        "detail": "Authentication credentials were not provided."
+    }
+
+
+def test_api_documents_public_search_anonymous_on_authenticated_document():
+    """Anonymous users cannot search on an authenticated-only document."""
+    client = APIClient()
+    document = factories.DocumentFactory(link_reach="authenticated")
+
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "anything"},
+    )
+    assert response.status_code == 401
+    assert response.json() == {
+        "detail": "Authentication credentials were not provided."
+    }
+
+
+def test_api_documents_public_search_authenticated_on_restricted_document():
+    """Authenticated users cannot search on a restricted document they don't own."""
+    user = factories.UserFactory()
+    document = factories.DocumentFactory(link_reach="restricted")
+
+    client = APIClient()
+    client.force_login(user)
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "anything"},
+    )
+    assert response.status_code == 403
+    assert response.json() == {
+        "detail": "You do not have permission to perform this action."
+    }
+
+
+def test_api_documents_public_search_authenticated_on_authenticated_document():
+    """Authenticated users cannot search on a authenticated document they don't own."""
+    user = factories.UserFactory()
+    document = factories.DocumentFactory(link_reach="authenticated")
+
+    client = APIClient()
+    client.force_login(user)
+    response = client.get(
+        f"/api/v1.0/documents/{document.id}/public_search/",
+        data={"q": "anything"},
+    )
+    assert response.status_code == 403
+    assert response.json() == {
+        "detail": "You do not have permission to perform this action."
+    }
+
+
+# ---------------------------------------------------------------------------
+# Public via ancestor
+# ---------------------------------------------------------------------------
+
+
+def test_api_documents_public_search_document_public_via_ancestor():
+    """
+    A restricted child document whose ancestor is public is effectively public.
+    The search scope should be rooted at the highest public ancestor.
+    """
+    client = APIClient()
+
+    root = factories.DocumentFactory(link_reach="public", title="root")
+    child = factories.DocumentFactory(
+        parent=root, link_reach="restricted", title="child alpha"
+    )
+    sibling = factories.DocumentFactory(parent=root, title="sibling alpha")
+    grand_child = factories.DocumentFactory(parent=child, title="grand alpha")
+
+    # child is public via root
+    assert child.computed_link_reach == models.LinkReachChoices.PUBLIC
+
+    response = client.get(
+        f"/api/v1.0/documents/{child.id}/public_search/",
+        data={"q": "alpha"},
+    )
+    assert response.status_code == 200
+
+    content = response.json()
+    result_ids = {r["id"] for r in content["results"]}
+
+    # All descendants of root that match "alpha" should be returned
+    assert len(result_ids) == 3
+    assert str(child.id) in result_ids
+    assert str(sibling.id) in result_ids
+    assert str(grand_child.id) in result_ids
+
+
+def test_api_documents_public_search_scope_limited_to_public_tree():
+    """
+    Documents outside the public tree should not appear in results, even if they
+    match the query.
+    """
+    client = APIClient()
+
+    private_root = factories.DocumentFactory(
+        link_reach="restricted", title="private root"
+    )
+    public_doc = factories.DocumentFactory(
+        parent=private_root, link_reach="public", title="public doc"
+    )
+    inside = factories.DocumentFactory(parent=public_doc, title="alpha inside")
+
+    # Separate tree — should never appear
+    other_root = factories.DocumentFactory(link_reach="public", title="other root")
+    outside = factories.DocumentFactory(parent=other_root, title="alpha outside")
+
+    response = client.get(
+        f"/api/v1.0/documents/{public_doc.id}/public_search/",
+        data={"q": "alpha"},
+    )
+    assert response.status_code == 200
+
+    result_ids = {r["id"] for r in response.json()["results"]}
+    assert len(result_ids) == 1
+    assert str(inside.id) in result_ids
+    assert str(outside.id) not in result_ids
+
+
+def test_api_documents_public_search_excludes_deleted_documents():
+    """Soft-deleted documents should not appear in results."""
+    client = APIClient()
+    root = factories.DocumentFactory(link_reach="public")
+    alive = factories.DocumentFactory(parent=root, title="alive alpha")
+    deleted = factories.DocumentFactory(
+        parent=root,
+        title="deleted alpha",
+        deleted_at="2024-01-01T00:00:00Z",
+        ancestors_deleted_at="2024-01-01T00:00:00Z",
+    )
+
+    response = client.get(
+        f"/api/v1.0/documents/{root.id}/public_search/",
+        data={"q": "alpha"},
+    )
+    assert response.status_code == 200
+
+    result_ids = {r["id"] for r in response.json()["results"]}
+    assert len(result_ids) == 1
+    assert str(alive.id) in result_ids
+    assert str(deleted.id) not in result_ids
+
+
+def test_api_documents_public_search_excludes_documents_with_deleted_ancestor():
+    """Documents whose ancestor is deleted should not appear in results."""
+    client = APIClient()
+    root = factories.DocumentFactory(link_reach="public")
+    deleted_parent = factories.DocumentFactory(
+        parent=root,
+        title="deleted parent",
+        deleted_at="2024-01-01T00:00:00Z",
+        ancestors_deleted_at="2024-01-01T00:00:00Z",
+    )
+    orphan = factories.DocumentFactory(
+        parent=deleted_parent,
+        title="orphan alpha",
+        ancestors_deleted_at="2024-01-01T00:00:00Z",
+    )
+    alive = factories.DocumentFactory(parent=root, title="alive alpha")
+
+    response = client.get(
+        f"/api/v1.0/documents/{root.id}/public_search/",
+        data={"q": "alpha"},
+    )
+
+    assert response.status_code == 200
+
+    result_ids = {r["id"] for r in response.json()["results"]}
+    assert len(result_ids) == 1
+    assert str(alive.id) in result_ids
+    assert str(orphan.id) not in result_ids
+
+
+# ---------------------------------------------------------------------------
+# Ordering
+# ---------------------------------------------------------------------------
+
+
+def test_api_documents_public_search_ordered_by_most_recent_first():
+    """Results should be ordered by -updated_at."""
+    client = APIClient()
+
+    root_doc = factories.DocumentFactory(link_reach="public")
+    old = factories.DocumentFactory(parent=root_doc, title="old alpha")
+    new = factories.DocumentFactory(parent=root_doc, title="new alpha")
+
+    # Force updated_at ordering
+    models.Document.objects.filter(pk=old.pk).update(
+        updated_at=timezone.now() - datetime.timedelta(days=10)
+    )
+    models.Document.objects.filter(pk=new.pk).update(updated_at=timezone.now())
+
+    response = client.get(
+        f"/api/v1.0/documents/{root_doc.id}/public_search/",
+        data={"q": "alpha"},
+    )
+    assert response.status_code == 200
+
+    result_ids = [r["id"] for r in response.json()["results"]]
+    assert len(result_ids) == 2
+    assert result_ids.index(str(new.id)) < result_ids.index(str(old.id))
diff --git a/src/backend/core/tests/documents/test_api_documents_retrieve.py b/src/backend/core/tests/documents/test_api_documents_retrieve.py
index f4a4876c..e92cd572 100644
--- a/src/backend/core/tests/documents/test_api_documents_retrieve.py
+++ b/src/backend/core/tests/documents/test_api_documents_retrieve.py
@@ -57,6 +57,7 @@ def test_api_documents_retrieve_anonymous_public_standalone():
             "media_check": True,
             "move": False,
             "partial_update": document.link_role == "editor",
+            "public_search": document.link_reach == "public",
             "restore": False,
             "retrieve": True,
             "search": True,
@@ -135,6 +136,7 @@ def test_api_documents_retrieve_anonymous_public_parent():
             "media_check": True,
             "move": False,
             "partial_update": grand_parent.link_role == "editor",
+            "public_search": True,
             "restore": False,
             "retrieve": True,
             "search": True,
@@ -246,6 +248,7 @@ def test_api_documents_retrieve_authenticated_unrelated_public_or_authenticated(
             "media_check": True,
             "move": False,
             "partial_update": document.link_role == "editor",
+            "public_search": document.link_reach == "public",
             "restore": False,
             "retrieve": True,
             "search": True,
@@ -331,6 +334,7 @@ def test_api_documents_retrieve_authenticated_public_or_authenticated_parent(rea
             "media_auth": True,
             "media_check": True,
             "partial_update": grand_parent.link_role == "editor",
+            "public_search": grand_parent.link_reach == "public",
             "restore": False,
             "retrieve": True,
             "search": True,
@@ -531,6 +535,7 @@ def test_api_documents_retrieve_authenticated_related_parent():
             "media_check": True,
             "move": access.role in ["administrator", "owner"],
             "partial_update": access.role not in ["reader", "commenter"],
+            "public_search": document.computed_link_reach == "public",
             "restore": access.role == "owner",
             "retrieve": True,
             "search": True,
diff --git a/src/backend/core/tests/documents/test_api_documents_trashbin.py b/src/backend/core/tests/documents/test_api_documents_trashbin.py
index a8ee8368..2e4b71e3 100644
--- a/src/backend/core/tests/documents/test_api_documents_trashbin.py
+++ b/src/backend/core/tests/documents/test_api_documents_trashbin.py
@@ -99,6 +99,7 @@ def test_api_documents_trashbin_format():
             "media_check": False,
             "move": False,  # Can't move a deleted document
             "partial_update": False,
+            "public_search": False,
             "restore": True,
             "retrieve": True,
             "search": False,
diff --git a/src/backend/core/tests/test_models_documents.py b/src/backend/core/tests/test_models_documents.py
index 82edf82d..08b13c7b 100644
--- a/src/backend/core/tests/test_models_documents.py
+++ b/src/backend/core/tests/test_models_documents.py
@@ -182,6 +182,7 @@ def test_models_documents_get_abilities_forbidden(
             "restricted": None,
         },
         "partial_update": False,
+        "public_search": document.computed_link_reach == "public",
         "restore": False,
         "retrieve": False,
         "tree": False,
@@ -249,6 +250,7 @@ def test_models_documents_get_abilities_reader(
         "media_check": True,
         "move": False,
         "partial_update": False,
+        "public_search": reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -321,6 +323,7 @@ def test_models_documents_get_abilities_commenter(
         "media_check": True,
         "move": False,
         "partial_update": False,
+        "public_search": reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -390,6 +393,7 @@ def test_models_documents_get_abilities_editor(
         "media_check": True,
         "move": False,
         "partial_update": True,
+        "public_search": reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -448,6 +452,7 @@ def test_models_documents_get_abilities_owner(django_assert_num_queries):
         "media_check": True,
         "move": True,
         "partial_update": True,
+        "public_search": document.computed_link_reach == "public",
         "restore": True,
         "retrieve": True,
         "tree": True,
@@ -492,6 +497,7 @@ def test_models_documents_get_abilities_owner(django_assert_num_queries):
         "media_check": False,
         "move": False,
         "partial_update": False,
+        "public_search": document.computed_link_reach == "public",
         "restore": True,
         "retrieve": True,
         "tree": True,
@@ -540,6 +546,7 @@ def test_models_documents_get_abilities_administrator(django_assert_num_queries)
         "media_check": True,
         "move": True,
         "partial_update": True,
+        "public_search": document.computed_link_reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -598,6 +605,7 @@ def test_models_documents_get_abilities_editor_user(django_assert_num_queries):
         "media_check": True,
         "move": False,
         "partial_update": True,
+        "public_search": document.computed_link_reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -664,6 +672,7 @@ def test_models_documents_get_abilities_reader_user(
         "media_check": True,
         "move": False,
         "partial_update": access_from_link,
+        "public_search": document.computed_link_reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -731,6 +740,7 @@ def test_models_documents_get_abilities_commenter_user(
         "media_check": True,
         "move": False,
         "partial_update": access_from_link,
+        "public_search": document.computed_link_reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -794,6 +804,7 @@ def test_models_documents_get_abilities_preset_role(django_assert_num_queries):
         "media_check": True,
         "move": False,
         "partial_update": False,
+        "public_search": access.document.computed_link_reach == "public",
         "restore": False,
         "retrieve": True,
         "tree": True,
@@ -1691,3 +1702,74 @@ def test_models_documents_compute_ancestors_links_paths_mapping_structure(
                 {"link_reach": sibling.link_reach, "link_role": sibling.link_role},
             ],
         }
+
+
+# get_highest_public_ancestor method
+
+
+def test_models_documents_get_highest_public_ancestor_root_public():
+    """A root document with public link reach should return itself."""
+    document = factories.DocumentFactory(link_reach="public")
+    assert document.get_highest_public_ancestor() == document
+
+
+def test_models_documents_get_highest_public_ancestor_root_restricted():
+    """A root document with restricted link reach should return None."""
+    document = factories.DocumentFactory(link_reach="restricted")
+    assert document.get_highest_public_ancestor() is None
+
+
+def test_models_documents_get_highest_public_ancestor_root_authenticated():
+    """A root document with authenticated link reach should return None."""
+    document = factories.DocumentFactory(link_reach="authenticated")
+    assert document.get_highest_public_ancestor() is None
+
+
+def test_models_documents_get_highest_public_ancestor_child_is_public():
+    """A child document that is itself public should return itself, not the parent."""
+    parent = factories.DocumentFactory(link_reach="restricted")
+    child = factories.DocumentFactory(parent=parent, link_reach="public")
+    assert child.get_highest_public_ancestor() == child
+
+
+def test_models_documents_get_highest_public_ancestor_parent_is_public():
+    """A child with restricted reach whose parent is public should return the parent."""
+    parent = factories.DocumentFactory(link_reach="public")
+    child = factories.DocumentFactory(parent=parent, link_reach="restricted")
+    assert child.get_highest_public_ancestor() == parent
+
+
+def test_models_documents_get_highest_public_ancestor_neither_public():
+    """A child with restricted reach and a restricted parent should return None."""
+    parent = factories.DocumentFactory(link_reach="restricted")
+    child = factories.DocumentFactory(parent=parent, link_reach="restricted")
+    assert child.get_highest_public_ancestor() is None
+
+
+def test_models_documents_get_highest_public_ancestor_grandparent_is_public():
+    """
+    Returns the highest public ancestor (grandparent) when only the grandparent is public.
+    """
+    grandparent = factories.DocumentFactory(link_reach="public")
+    parent = factories.DocumentFactory(parent=grandparent, link_reach="restricted")
+    child = factories.DocumentFactory(parent=parent, link_reach="restricted")
+    assert child.get_highest_public_ancestor() == grandparent
+
+
+def test_models_documents_get_highest_public_ancestor_deep_tree_only_middle_public():
+    """
+    When only a middle ancestor is public, it is returned as the highest public ancestor.
+    """
+    root_doc = factories.DocumentFactory(link_reach="restricted")
+    middle = factories.DocumentFactory(parent=root_doc, link_reach="public")
+    child = factories.DocumentFactory(parent=middle, link_reach="restricted")
+    grandchild = factories.DocumentFactory(parent=child, link_reach="restricted")
+    assert grandchild.get_highest_public_ancestor() == middle
+
+
+def test_models_documents_get_highest_public_ancestor_all_restricted_deep():
+    """A deeply nested document with no public ancestor should return None."""
+    root_doc = factories.DocumentFactory(link_reach="restricted")
+    child = factories.DocumentFactory(parent=root_doc, link_reach="restricted")
+    grandchild = factories.DocumentFactory(parent=child, link_reach="restricted")
+    assert grandchild.get_highest_public_ancestor() is None