diff --git a/openedx/core/djangoapps/content/search/documents.py b/openedx/core/djangoapps/content/search/documents.py
index 51eca8816430..e45c9fb3f634 100644
--- a/openedx/core/djangoapps/content/search/documents.py
+++ b/openedx/core/djangoapps/content/search/documents.py
@@ -61,6 +61,10 @@ class Fields:
     # Text (html) blocks have an "html_content" key in here, capa has "capa_content" and "problem_types", and so on.
     content = "content"
 
+    # Collections use this field to communicate how many entities/components they contain.
+    # Structural XBlocks may use this one day to indicate how many child blocks they ocntain.
+    num_children = "num_children"
+
     # Note: new fields or values can be added at any time, but if they need to be indexed for filtering or keyword
     # search, the index configuration will need to be changed, which is only done as part of the 'reindex_studio'
     # command (changing those settings on an large active index is not recommended).
@@ -344,6 +348,7 @@ def searchable_doc_for_collection(collection) -> dict:
         # If related contentlibrary is found, it will override this value below.
         # Mostly contentlibrary.library_key == learning_package.key
         Fields.context_key: collection.learning_package.key,
+        Fields.num_children: collection.entities.count(),
     }
     # Just in case learning_package is not related to a library
     try:
diff --git a/openedx/core/djangoapps/content/search/tests/test_api.py b/openedx/core/djangoapps/content/search/tests/test_api.py
index d075681798bc..ec9975724753 100644
--- a/openedx/core/djangoapps/content/search/tests/test_api.py
+++ b/openedx/core/djangoapps/content/search/tests/test_api.py
@@ -190,6 +190,7 @@ def setUp(self):
             "type": "collection",
             "display_name": "my_collection",
             "description": "my collection description",
+            "num_children": 0,
             "context_key": "lib:org1:lib",
             "org": "org1",
             "created": created_date.timestamp(),
@@ -453,6 +454,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "type": "collection",
             "display_name": "Collection 1",
             "description": "First Collection",
+            "num_children": 0,
             "context_key": "lib:org1:lib",
             "org": "org1",
             "created": created_date.timestamp(),
@@ -465,6 +467,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "type": "collection",
             "display_name": "Collection 2",
             "description": "Second Collection",
+            "num_children": 0,
             "context_key": "lib:org1:lib",
             "org": "org1",
             "created": created_date.timestamp(),
@@ -477,6 +480,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "type": "collection",
             "display_name": "Collection 2",
             "description": "Second Collection",
+            "num_children": 1,
             "context_key": "lib:org1:lib",
             "org": "org1",
             "created": created_date.timestamp(),
@@ -489,6 +493,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "type": "collection",
             "display_name": "Collection 1",
             "description": "First Collection",
+            "num_children": 1,
             "context_key": "lib:org1:lib",
             "org": "org1",
             "created": created_date.timestamp(),
diff --git a/openedx/core/djangoapps/content/search/tests/test_documents.py b/openedx/core/djangoapps/content/search/tests/test_documents.py
index d972c9ac4956..90ac9c1a70bb 100644
--- a/openedx/core/djangoapps/content/search/tests/test_documents.py
+++ b/openedx/core/djangoapps/content/search/tests/test_documents.py
@@ -299,6 +299,7 @@ def test_collection_with_library(self):
             "org": "edX",
             "display_name": "Toy Collection",
             "description": "my toy collection description",
+            "num_children": 1,
             "context_key": "lib:edX:2012_Fall",
             "access_id": self.library_access_id,
             "breadcrumbs": [{"display_name": "some content_library"}],
@@ -327,6 +328,7 @@ def test_collection_with_no_library(self):
             "type": "collection",
             "display_name": "my_collection",
             "description": "my collection description",
+            "num_children": 0,
             "context_key": learning_package.key,
             "access_id": self.toy_course_access_id,
             "breadcrumbs": [{"display_name": "some learning_package"}],