diff --git a/changelog.d/22090_remove_gcp_pubsub_msg_size_limit.fix.md b/changelog.d/22090_remove_gcp_pubsub_msg_size_limit.fix.md
new file mode 100644
index 0000000000000..c7323afe4ff89
--- /dev/null
+++ b/changelog.d/22090_remove_gcp_pubsub_msg_size_limit.fix.md
@@ -0,0 +1,3 @@
+The `gcp_pubsub` source no longer has a 4MB message size limit.
+
+authors: sbalmos
diff --git a/src/sources/gcp_pubsub.rs b/src/sources/gcp_pubsub.rs
index ea26e00de53ea..3fce9bb605046 100644
--- a/src/sources/gcp_pubsub.rs
+++ b/src/sources/gcp_pubsub.rs
@@ -479,7 +479,9 @@ impl PubsubSource {
                 }
                 Ok(req)
             },
-        );
+        )
+        // Tonic added a default of 4MB in 0.9. This replaces the old behavior.
+        .max_decoding_message_size(usize::MAX);
 
         let (ack_ids_sender, ack_ids_receiver) = mpsc::channel(ACK_QUEUE_SIZE);