diff --git a/finagle/h2/src/main/scala/com/twitter/finagle/buoyant/h2/netty4/Netty4Message.scala b/finagle/h2/src/main/scala/com/twitter/finagle/buoyant/h2/netty4/Netty4Message.scala
index 3c337efdbf..99066f7bd7 100644
--- a/finagle/h2/src/main/scala/com/twitter/finagle/buoyant/h2/netty4/Netty4Message.scala
+++ b/finagle/h2/src/main/scala/com/twitter/finagle/buoyant/h2/netty4/Netty4Message.scala
@@ -102,10 +102,19 @@ private[h2] object Netty4Message {
 
     def apply(f: Http2DataFrame, updateWindow: Int => Future[Unit]): Frame.Data = {
       val sz = f.content.readableBytes + f.padding
-      val buf = ByteBufAsBuf(f.content)
+      val buf = ByteBufAsBuf(f.content.retain())
       val releaser: () => Future[Unit] =
-        if (sz > 0) () => updateWindow(sz)
-        else () => Future.Unit
+        () =>
+          {
+            // When releasing the frame, call `updateWindow` with the frame's
+            // size to release the frame's window capacity.
+            val res = if (sz > 0) updateWindow(sz) else Future.Unit
+            // Because `ByteBufAsBuf` does not support reference counting,
+            // it's necessary to call `.release()` on the underlying `ByteBuf`
+            // when releasing the data frame.
+            f.content.release()
+            res
+          }
       Frame.Data(buf, f.isEndStream, releaser)
     }
   }