diff --git a/src/smart-map.spec.ts b/src/smart-map.spec.ts
index 4bf0c50..b0b9653 100644
--- a/src/smart-map.spec.ts
+++ b/src/smart-map.spec.ts
@@ -23,8 +23,9 @@ describe('SmartMap Class', () => {
     map.set(true, 'boolean');
     map.set(Symbol(), 'symbol');
     map.set(undefined, 'undefined');
+    map.set(null, 'null');
 
-    expect(map.size).toBe(5);
+    expect(map.size).toBe(6);
   });
 
   it('should set a value by object type keys', () => {
@@ -58,9 +59,11 @@ describe('SmartMap Class', () => {
 
     map.set(1, '1');
     map.set(anObj, 'an object');
+    map.set(null, 'null');
 
     expect(map.get(1)).toBe('1');
     expect(map.get(anObj)).toBe('an object');
+    expect(map.get(null)).toBe('null');
   });
 
   it('should delete value when delete method called via both primitive and object key', () => {
diff --git a/src/smart-map.ts b/src/smart-map.ts
index 62d5281..07e275d 100644
--- a/src/smart-map.ts
+++ b/src/smart-map.ts
@@ -108,6 +108,6 @@ export class SmartMap<K = any, V = any> extends Map<K, V> {
    * @returns A boolean whether if the key is storable in weakmap or not
    */
   protected isStorableInWeakMap(key: K): boolean {
-    return SmartMap.TYPES_TO_STORE_IN_WEAKMAP.some(_key => typeof key === _key);
+    return key !== null && SmartMap.TYPES_TO_STORE_IN_WEAKMAP.some(_key => typeof key === _key);
   }
 }