diff --git a/targets/TARGET_STM/mbed_rtx.h b/targets/TARGET_STM/mbed_rtx.h
index 5bdba66735..7cd2082961 100644
--- a/targets/TARGET_STM/mbed_rtx.h
+++ b/targets/TARGET_STM/mbed_rtx.h
@@ -52,7 +52,8 @@
 #elif defined(TARGET_STM32F303VC)
 #define INITIAL_SP              (0x2000A000UL)
 
-#elif defined(TARGET_STM32L432KC)
+#elif defined(TARGET_STM32L432KC) ||\
+      defined (TARGET_STM32L433RC)
 #define INITIAL_SP              (0x20010000UL)
 
 #elif (defined(TARGET_STM32F303RE) ||\