diff --git a/lib/types/map.js b/lib/types/map.js
index d63cd403523..4b8607df311 100644
--- a/lib/types/map.js
+++ b/lib/types/map.js
@@ -119,7 +119,7 @@ class MongooseMap extends Map {
           v.$__.wasPopulated = { value: v._id };
           return v;
         });
-      } else {
+      } else if (value != null) {
         if (value.$__ == null) {
           value = new populated.options[populateModelSymbol](value);
         }