diff --git a/tokio-stream/src/stream_map.rs b/tokio-stream/src/stream_map.rs
index 80a521ee1..215980474 100644
--- a/tokio-stream/src/stream_map.rs
+++ b/tokio-stream/src/stream_map.rs
@@ -585,6 +585,15 @@ where
     }
 }
 
+impl<K, V> Extend<(K, V)> for StreamMap<K, V> {
+    fn extend<T>(&mut self, iter: T)
+    where
+        T: IntoIterator<Item = (K, V)>,
+    {
+        self.entries.extend(iter);
+    }
+}
+
 mod rand {
     use std::cell::Cell;