diff --git a/google/cloud/aiplatform/v1/content.proto b/google/cloud/aiplatform/v1/content.proto
index ea10d37dd8..d9f130f06d 100644
--- a/google/cloud/aiplatform/v1/content.proto
+++ b/google/cloud/aiplatform/v1/content.proto
@@ -658,6 +658,11 @@ message GroundingChunk {
 
     // Text of the attribution.
     optional string text = 3;
+
+    // Output only. The full document name for the referenced Vertex AI Search
+    // document.
+    optional string document_name = 6
+        [(google.api.field_behavior) = OUTPUT_ONLY];
   }
 
   // Chunk from Google Maps.
diff --git a/google/cloud/aiplatform/v1beta1/content.proto b/google/cloud/aiplatform/v1beta1/content.proto
index 237844fd84..b8449e0f3a 100644
--- a/google/cloud/aiplatform/v1beta1/content.proto
+++ b/google/cloud/aiplatform/v1beta1/content.proto
@@ -747,6 +747,11 @@ message GroundingChunk {
 
     // Text of the attribution.
     optional string text = 3;
+
+    // Output only. The full document name for the referenced Vertex AI Search
+    // document.
+    optional string document_name = 6
+        [(google.api.field_behavior) = OUTPUT_ONLY];
   }
 
   // Chunk from Google Maps.