diff --git a/web/src/hooks/queries/useAllUserCollections.test.ts b/web/src/hooks/queries/useAllUserCollections.test.ts
new file mode 100644
index 00000000..70b4eac6
--- /dev/null
+++ b/web/src/hooks/queries/useAllUserCollections.test.ts
@@ -0,0 +1,69 @@
+import { describe, expect, it } from "vitest";
+import type { LibraryCollection } from "@/api/types";
+import { buildAllUserCollectionOptions } from "./useAllUserCollections";
+
+function libraryCollection(id: string, title: string): LibraryCollection {
+  return {
+    id,
+    title,
+    collection_type: "smart",
+    source_config: {},
+    last_sync_status: "success",
+  } as LibraryCollection;
+}
+
+describe("buildAllUserCollectionOptions", () => {
+  it("keeps personal collections first and identifies their source", () => {
+    const options = buildAllUserCollectionOptions(
+      [{ id: 1, name: "Movies" }],
+      [{ id: "personal", name: "Weekend Picks" }],
+      [[libraryCollection("library", "Staff Picks")]],
+    );
+
+    expect(options.map(({ id, source, group }) => ({ id, source, group }))).toEqual([
+      { id: "personal", source: "user", group: "My Collections" },
+      { id: "library", source: "library", group: "Movies" },
+    ]);
+  });
+
+  it("lists a multi-library collection once with its combined scope", () => {
+    const shared = libraryCollection("shared", "Network Originals");
+
+    const options = buildAllUserCollectionOptions(
+      [
+        { id: 1, name: "Movies" },
+        { id: 2, name: "TV Shows" },
+      ],
+      undefined,
+      [[shared], [shared]],
+    );
+
+    expect(options).toHaveLength(1);
+    expect(options[0]).toMatchObject({
+      id: "shared",
+      title: "Network Originals",
+      source: "library",
+      group: "Movies, TV Shows",
+      library_name: "Movies, TV Shows",
+    });
+  });
+
+  it("keeps separate same-titled collections distinct", () => {
+    const options = buildAllUserCollectionOptions(
+      [
+        { id: 1, name: "Movies" },
+        { id: 2, name: "TV Shows" },
+      ],
+      undefined,
+      [
+        [libraryCollection("movies", "Network Originals")],
+        [libraryCollection("shows", "Network Originals")],
+      ],
+    );
+
+    expect(options.map(({ id, group }) => ({ id, group }))).toEqual([
+      { id: "movies", group: "Movies" },
+      { id: "shows", group: "TV Shows" },
+    ]);
+  });
+});
diff --git a/web/src/hooks/queries/useAllUserCollections.ts b/web/src/hooks/queries/useAllUserCollections.ts
index 99e0495b..51095dfa 100644
--- a/web/src/hooks/queries/useAllUserCollections.ts
+++ b/web/src/hooks/queries/useAllUserCollections.ts
@@ -1,5 +1,5 @@
 import { useQueries } from "@tanstack/react-query";
-import type { LibraryCollection } from "@/api/types";
+import type { Collection, LibraryCollection } from "@/api/types";
 import { useUserLibraries } from "./libraries";
 import { useCollections } from "./collections";
 import { getLibraryCollectionList, libraryCollectionsQueryOptions } from "./libraryCollections";
@@ -16,6 +16,60 @@ export interface CollectionOption {
   last_sync_status?: LibraryCollection["last_sync_status"];
 }
 
+type LibrarySummary = { id: number; name: string };
+type UserCollectionSummary = Pick<Collection, "id" | "name">;
+
+export function buildAllUserCollectionOptions(
+  libraries: readonly LibrarySummary[],
+  userCollections: readonly UserCollectionSummary[] | undefined,
+  libraryCollectionsByLibrary: ReadonlyArray<readonly LibraryCollection[] | undefined>,
+): CollectionOption[] {
+  const collections: CollectionOption[] = [];
+
+  for (const collection of userCollections ?? []) {
+    collections.push({
+      id: collection.id,
+      title: collection.name,
+      source: "user",
+      group: "My Collections",
+    });
+  }
+
+  const libraryOptions = new Map<string, { option: CollectionOption; libraryNames: string[] }>();
+
+  for (let i = 0; i < libraries.length; i++) {
+    const library = libraries[i]!;
+    for (const collection of libraryCollectionsByLibrary[i] ?? []) {
+      const existing = libraryOptions.get(collection.id);
+      if (existing) {
+        if (!existing.libraryNames.includes(library.name)) {
+          existing.libraryNames.push(library.name);
+          const group = existing.libraryNames.join(", ");
+          existing.option.group = group;
+          existing.option.library_name = group;
+        }
+        continue;
+      }
+
+      const option: CollectionOption = {
+        id: collection.id,
+        title: collection.title,
+        source: "library",
+        group: library.name,
+        library_id: library.id,
+        library_name: library.name,
+        collection_type: collection.collection_type,
+        source_config: collection.source_config,
+        last_sync_status: collection.last_sync_status,
+      };
+      libraryOptions.set(collection.id, { option, libraryNames: [library.name] });
+      collections.push(option);
+    }
+  }
+
+  return collections;
+}
+
 export function useAllUserCollections() {
   const { data: libraries } = useUserLibraries();
   const { data: userCollections, isLoading: userCollectionsLoading } = useCollections();
@@ -29,41 +83,14 @@ export function useAllUserCollections() {
 
   const isLoading = libraryQueries.some((q) => q.isLoading) || userCollectionsLoading;
 
-  const collections: CollectionOption[] = [];
-
-  // Add personal user collections first (grouped under "My Collections").
-  if (userCollections) {
-    for (const c of userCollections) {
-      collections.push({
-        id: c.id,
-        title: c.name,
-        source: "user",
-        group: "My Collections",
-      });
-    }
-  }
-
-  // Add library collections grouped by library name.
-  if (libraries) {
-    for (let i = 0; i < libraries.length; i++) {
-      const lib = libraries[i]!;
-      const result = libraryQueries[i];
-      const libraryCollections = Array.isArray(result?.data) ? result.data : [];
-      for (const c of libraryCollections) {
-        collections.push({
-          id: c.id,
-          title: c.title,
-          source: "library",
-          group: lib.name,
-          library_id: lib.id,
-          library_name: lib.name,
-          collection_type: c.collection_type,
-          source_config: c.source_config,
-          last_sync_status: c.last_sync_status,
-        });
-      }
-    }
-  }
+  const libraryCollectionsByLibrary = libraryQueries.map((result) =>
+    Array.isArray(result.data) ? result.data : undefined,
+  );
+  const collections = buildAllUserCollectionOptions(
+    libraries ?? [],
+    userCollections,
+    libraryCollectionsByLibrary,
+  );
 
   return { collections, isLoading };
 }