diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3ca214f1..e4b15ba0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Fixed `-Wparentheses` warning introduced in v5.6.5 (PR #335 by @nuket)
+
 v5.6.5
 ------
 
diff --git a/include/ArduinoJson/JsonVariant.hpp b/include/ArduinoJson/JsonVariant.hpp
index df573b23..f0953cf5 100644
--- a/include/ArduinoJson/JsonVariant.hpp
+++ b/include/ArduinoJson/JsonVariant.hpp
@@ -330,8 +330,8 @@ class JsonVariant : public JsonVariantBase<JsonVariant> {
   }
   bool isString() const {
     return _type == Internals::JSON_STRING ||
-           _type == Internals::JSON_UNPARSED && _content.asString &&
-               !strcmp("null", _content.asString);
+           (_type == Internals::JSON_UNPARSED && _content.asString &&
+            !strcmp("null", _content.asString));
   }
 
   // The current type of the variant
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index ea8074a8..66917a9d 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -25,7 +25,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
 		-Wformat=2
 		-Winit-self
 		-Wmissing-include-dirs
-		-Wno-parentheses
+		-Wparentheses
 		-Wno-sign-conversion
 		-Wno-unused
 		-Wno-variadic-macros