diff --git a/cmake/toolchains/ARM.cmake b/cmake/toolchains/ARM.cmake
index 254744f817..ac7995bbb1 100644
--- a/cmake/toolchains/ARM.cmake
+++ b/cmake/toolchains/ARM.cmake
@@ -11,7 +11,6 @@ list(APPEND common_options
     "${MBED_STUDIO_ARM_COMPILER}"
     "-c"
     "--target=arm-arm-none-eabi"
-    "-Oz"
     "-Wno-armcc-pragma-push-pop"
     "-Wno-armcc-pragma-anon-unions"
     "-Wno-reserved-user-defined-literal"
diff --git a/cmake/toolchains/GCC_ARM.cmake b/cmake/toolchains/GCC_ARM.cmake
index 214e885b36..82ef6e7e7a 100644
--- a/cmake/toolchains/GCC_ARM.cmake
+++ b/cmake/toolchains/GCC_ARM.cmake
@@ -31,7 +31,6 @@ list(APPEND common_options
     "-funsigned-char"
     "-MMD"
     "-fomit-frame-pointer"
-    "-Os"
     "-g"
 )