diff --git a/src/system/SystemConfig.h b/src/system/SystemConfig.h
index dceac0f8a49479..fba85f5caafc4f 100644
--- a/src/system/SystemConfig.h
+++ b/src/system/SystemConfig.h
@@ -121,7 +121,7 @@
 #error "FORBIDDEN: CHIP_SYSTEM_CONFIG_MULTICAST_HOMING CAN ONLY BE USED WITH SOCKET IMPL"
 #endif
 
-#if CHIP_SYSTEM_CONFIG_MULTICAST_HOMING && CHIP_SYSTEM_CONFIG_USE_SOCKETS && __ZEPHYR__
+#if CHIP_SYSTEM_CONFIG_MULTICAST_HOMING && CHIP_SYSTEM_CONFIG_USE_SOCKETS && defined(__ZEPHYR__)
 #error "FORBIDDEN: CHIP_SYSTEM_CONFIG_MULTICAST_HOMING WAS NOT TESTED WITH ZEPHYR"
 #endif
 
@@ -639,7 +639,7 @@ struct LwIPEvent;
  *  Defaults to enabled if the system is using sockets (except for Zephyr RTOS).
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_POSIX_PIPE
-#if (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK) && !__ZEPHYR__ && !__MBED__
+#if (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK) && !defined(__ZEPHYR__) && !defined(__MBED__)
 #define CHIP_SYSTEM_CONFIG_USE_POSIX_PIPE 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_POSIX_PIPE 0
@@ -658,7 +658,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Zephyr platforms using sockets
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKET_EXTENSIONS
-#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && __ZEPHYR__
+#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && defined(__ZEPHYR__)
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKET_EXTENSIONS 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKET_EXTENSIONS 0
@@ -679,7 +679,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Zephyr platforms using sockets
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_PLATFORM_MULTICAST_API
-#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && __ZEPHYR__
+#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && defined(__ZEPHYR__)
 #define CHIP_SYSTEM_CONFIG_USE_PLATFORM_MULTICAST_API 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_PLATFORM_MULTICAST_API 0
@@ -695,7 +695,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Zephyr platforms using sockets
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_ZEPHYR_NET_IF
-#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && __ZEPHYR__
+#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && defined(__ZEPHYR__)
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_NET_IF 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_NET_IF 0
@@ -711,7 +711,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Unix/Linux platforms using sockets
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_BSD_IFADDRS
-#if (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK) && !__ZEPHYR__
+#if (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK) && !defined(__ZEPHYR__)
 #define CHIP_SYSTEM_CONFIG_USE_BSD_IFADDRS 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_BSD_IFADDRS 0
@@ -727,7 +727,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Zephyr platforms that do not enable Zephyr POSIX layer.
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKETS
-#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && __ZEPHYR__ && CONFIG_NET_SOCKETS_POSIX_NAMES
+#if CHIP_SYSTEM_CONFIG_USE_SOCKETS && defined(__ZEPHYR__) && CONFIG_NET_SOCKETS_POSIX_NAMES
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKETS 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_SOCKETS 0
@@ -759,7 +759,7 @@ struct LwIPEvent;
  *  Defaults to enabled on Zephyr platforms that enable CONFIG_EVENTFD.
  */
 #ifndef CHIP_SYSTEM_CONFIG_USE_ZEPHYR_EVENTFD
-#if __ZEPHYR__ && CONFIG_EVENTFD
+#if defined(__ZEPHYR__) && CONFIG_EVENTFD
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_EVENTFD 1
 #else
 #define CHIP_SYSTEM_CONFIG_USE_ZEPHYR_EVENTFD 0
diff --git a/src/system/SystemError.h b/src/system/SystemError.h
index 37abd6c0b2257a..5bc4b79d1ebf1e 100644
--- a/src/system/SystemError.h
+++ b/src/system/SystemError.h
@@ -59,7 +59,7 @@ extern const char * DescribeErrorPOSIX(CHIP_ERROR code);
 extern void RegisterPOSIXErrorFormatter();
 extern bool FormatPOSIXError(char * buf, uint16_t bufSize, CHIP_ERROR err);
 
-#if __ZEPHYR__
+#ifdef __ZEPHYR__
 extern CHIP_ERROR MapErrorZephyr(int code);
 #endif // __ZEPHYR__