diff --git a/source/common/json/json_loader.cc b/source/common/json/json_loader.cc
index ecf618c3770b..8a4a79d9cafb 100644
--- a/source/common/json/json_loader.cc
+++ b/source/common/json/json_loader.cc
@@ -307,6 +307,10 @@ void Field::buildRapidJsonDocument(const Field& field, rapidjson::Value& value,
     }
     break;
   }
+  case Type::Null: {
+    value.SetNull();
+    break;
+  }
   default:
     NOT_REACHED;
   }
diff --git a/test/common/json/json_loader_test.cc b/test/common/json/json_loader_test.cc
index e2bcebcfe659..df0978aceb11 100644
--- a/test/common/json/json_loader_test.cc
+++ b/test/common/json/json_loader_test.cc
@@ -445,6 +445,11 @@ TEST(JsonLoaderTest, YamlObject) {
   }
 }
 
+TEST(JsonLoaderTest, YamlAsJsonString) {
+  const Json::ObjectSharedPtr json = Json::Factory::loadFromYamlString("");
+  EXPECT_EQ(json->asJsonString(), "null");
+}
+
 TEST(JsonLoaderTest, BadYamlException) {
   std::string bad_yaml = R"EOF(
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