diff --git a/src/dfo_docs/manifest.py b/src/dfo_docs/manifest.py
index 83ab1b4..a8fd3ae 100644
--- a/src/dfo_docs/manifest.py
+++ b/src/dfo_docs/manifest.py
@@ -362,7 +362,7 @@ def _build_source_nav(
     and recursively for each nested grouping heading inside it.
     """
     landing: str | None = None
-    if entries and len(entries[0].breadcrumb) == depth and _is_index(entries[0].file):
+    if _leads_with_landing(entries, depth=depth):
         landing = _page_id(source_name, _page_slug(entries[0].file))
         entries = entries[1:]
 
@@ -416,6 +416,16 @@ def _group_id(key_path: tuple[str, ...]) -> str:
     return "group:" + "/".join(key_path)
 
 
+def _leads_with_landing(entries: Sequence[NavEntry], *, depth: int) -> bool:
+    """Whether `entries`, one nav group's flattened entries at `depth`, open with the
+    group's own `index.md`, which `_build_source_nav` folds into the group's landing."""
+    return (
+        bool(entries)
+        and len(entries[0].breadcrumb) == depth
+        and _is_index(entries[0].file)
+    )
+
+
 def _is_index(file: str) -> bool:
     return PurePosixPath(file).name == "index.md"
 
@@ -433,6 +443,9 @@ def _source_pages(
     *,
     corpus_root: Path,
 ) -> list[Page]:
+    landing_file = (
+        sidecar.nav[0].file if _leads_with_landing(sidecar.nav, depth=0) else None
+    )
     return [
         _fetched_page(
             fetched,
@@ -440,7 +453,11 @@ def _source_pages(
             file=nav_entry.file,
             slug=_page_slug(nav_entry.file),
             path_prefix=sidecar.path,
-            title=nav_entry.title or nav_entry.file,
+            title=(
+                sidecar.title
+                if nav_entry.file == landing_file
+                else nav_entry.title or nav_entry.file
+            ),
             kind=PageKind.PAGE,
             corpus_root=corpus_root,
             excluded=sidecar.excluded,
diff --git a/tests/docsync/test_pages.py b/tests/docsync/test_pages.py
index effcb68..a30fe45 100644
--- a/tests/docsync/test_pages.py
+++ b/tests/docsync/test_pages.py
@@ -164,7 +164,7 @@ def test_pages_follow_the_nav_with_their_sections_and_titles(tmp_path):
     assert [(p.page_id, p.section_path, p.title) for p in pages] == [
         ("hub", (), "Home"),
         ("hub/build/share", ("Build",), "Share"),
-        ("guide", ("Build", "Guide"), "Guide home"),
+        ("guide", ("Build", "Guide"), "Guide"),
         ("guide/start", ("Build", "Guide"), "Start"),
         ("guide/deep", ("Build", "Guide", "Deep"), "Deep"),
         ("guide/deep/detail", ("Build", "Guide", "Deep"), "Detail"),
diff --git a/tests/test_manifest.py b/tests/test_manifest.py
index aeba756..1b4e383 100644
--- a/tests/test_manifest.py
+++ b/tests/test_manifest.py
@@ -509,6 +509,49 @@ def test_mount_group_folds_leading_index_into_page_id_and_path(tmp_path):
     assert [child.title for child in guides_group.children] == ["Advanced"]
 
 
+def test_source_index_page_takes_the_source_title_not_its_nav_label(tmp_path):
+    """A source that labels its landing `Home: index.md` still publishes that page
+    under the source's title, matching its group; other pages, including a later
+    top-level `index.md` leaf, keep their nav label."""
+    repo = _make_repo(tmp_path, "labelled")
+    (repo / "mkdocs.yml").write_text(
+        "site_name: tools/labelled\n"
+        "title: Labelled Reader\n"
+        "nav:\n"
+        "  - Home: index.md\n"
+        "  - Changelog: changelog.md\n"
+        "  - Reference: reference/index.md\n"
+        "  - Guides:\n"
+        "      - Home: guides/index.md\n"
+        "      - Advanced: guides/advanced.md\n"
+    )
+    docs = repo / "docs"
+    (docs / "guides").mkdir(parents=True)
+    (docs / "reference").mkdir()
+    for name in (
+        "index",
+        "changelog",
+        "reference/index",
+        "guides/index",
+        "guides/advanced",
+    ):
+        (docs / f"{name}.md").write_text(f"# {name}\n")
+    _commit_all(repo, "init")
+    source = _sample_source(repo, name="labelled", path="tools/labelled")
+    fetched = _fetch(source, tmp_path)
+    hub = HubNode(children=(HubNode(mount="labelled"),))
+
+    _, pages, _ = _build(
+        tmp_path, sources={"labelled": source}, hub=hub, fetched=[fetched]
+    )
+
+    assert _by_id(pages, "labelled").title == "Labelled Reader"
+    assert _by_id(pages, "labelled/changelog").title == "Changelog"
+    # Only the leading index is the landing; a later top-level index is a leaf.
+    assert _by_id(pages, "labelled/reference").title == "Reference"
+    assert _by_id(pages, "labelled/guides").title == "Home"
+
+
 def test_nav_node_ids_join_to_pages_and_groups_are_opaque(tmp_path):
     repo = _sample_repo(tmp_path)
     source = _sample_source(repo, path="tools/sample")