diff --git a/Cargo.toml b/Cargo.toml
index 653ca6d..a53e0be 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "trait-bound-typemap"
-version = "0.3.0"
+version = "0.3.1"
 edition = "2021"
 license = "Apache-2.0"
 readme = "README.md"
diff --git a/src/macros.rs b/src/macros.rs
index 2c3ae05..d97caa7 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -80,6 +80,17 @@ macro_rules! impl_typemap {
                 $map($crate::type_indexed::TypeIndexedMap(map))
             }
         }
+
+        impl<K: $crate::MapKey<Map = M>, M: 'static $(+ $trt )+> Extend<$crate::TypeMapEntry<K>> for $map {
+            fn extend<T: IntoIterator<Item = $crate::TypeMapEntry<K>>>(&mut self, iter: T) {
+                let iter = iter
+                    .into_iter()
+                    .map(|e: $crate::TypeMapEntry<K>| (e.type_id, e.mto))
+                    .collect::<Vec<(std::any::TypeId, multi_trait_object::MultitraitObject)>>();
+                self.0.extend(iter)
+            }
+        }
+
     };
 }
 
diff --git a/src/tests.rs b/src/tests.rs
index e2ea714..d941583 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -97,8 +97,23 @@ fn it_converts() {
     let mut clone_send_sync_map = CloneSendSyncTypeMap::new();
     clone_send_sync_map.insert::<TestStructKey>(TestStruct::default());
     assert!(clone_send_sync_map.contains_key::<TestStructKey>());
+
     let clone_map = CloneTypeMap::from_iter(clone_send_sync_map);
     assert!(clone_map.contains_key::<TestStructKey>());
+
     let any_map = AnyTypeMap::from_iter(clone_map);
     assert!(any_map.contains_key::<TestStructKey>());
 }
+
+#[test]
+fn it_can_be_extended() {
+    let mut clone_send_sync_map = CloneSendSyncTypeMap::new();
+    clone_send_sync_map.insert::<TestStructKey>(TestStruct::default());
+    assert!(clone_send_sync_map.contains_key::<TestStructKey>());
+
+    let mut clone_map = CloneTypeMap::new();
+    clone_map.insert::<TestStruct2Key>(TestStruct2::default());
+    clone_map.extend(clone_send_sync_map);
+    assert!(clone_map.contains_key::<TestStructKey>());
+    assert!(clone_map.contains_key::<TestStruct2Key>());
+}
diff --git a/src/type_indexed.rs b/src/type_indexed.rs
index 306a932..54ba1e9 100644
--- a/src/type_indexed.rs
+++ b/src/type_indexed.rs
@@ -1,4 +1,5 @@
 use std::any::TypeId;
+use std::collections::hash_map::IntoIter;
 use std::collections::HashMap;
 
 /// Base typemap used for implementation but not elsewhere
@@ -45,3 +46,18 @@ impl<T> TypeIndexedMap<T> {
         self.0.contains_key(&TypeId::of::<K>())
     }
 }
+
+impl<T> IntoIterator for TypeIndexedMap<T> {
+    type Item = (TypeId, T);
+    type IntoIter = IntoIter<TypeId, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.0.into_iter()
+    }
+}
+
+impl<T> Extend<(TypeId, T)> for TypeIndexedMap<T> {
+    fn extend<I: IntoIterator<Item = (TypeId, T)>>(&mut self, iter: I) {
+        self.0.extend(iter)
+    }
+}