diff --git a/tonic/src/metadata/mod.rs b/tonic/src/metadata/mod.rs
index 4e796748f..dff62fa2d 100644
--- a/tonic/src/metadata/mod.rs
+++ b/tonic/src/metadata/mod.rs
@@ -13,6 +13,7 @@ pub use self::key::MetadataKey;
 pub use self::map::Entry;
 pub use self::map::GetAll;
 pub use self::map::Iter;
+pub use self::map::IterMut;
 pub use self::map::KeyAndMutValueRef;
 pub use self::map::KeyAndValueRef;
 pub use self::map::KeyRef;
@@ -25,6 +26,7 @@ pub use self::map::ValueIter;
 pub use self::map::ValueRef;
 pub use self::map::ValueRefMut;
 pub use self::map::Values;
+pub use self::map::ValuesMut;
 pub use self::value::AsciiMetadataValue;
 pub use self::value::BinaryMetadataValue;
 pub use self::value::MetadataValue;