diff --git a/TESTS/mbedmicro-rtos-mbed/mutex/main.cpp b/TESTS/mbedmicro-rtos-mbed/mutex/main.cpp
index 38a0c7708c..a85b86a9c7 100644
--- a/TESTS/mbedmicro-rtos-mbed/mutex/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/mutex/main.cpp
@@ -32,6 +32,8 @@
     #define STACK_SIZE 768
 #elif (defined(TARGET_EFM32GG_STK3700)) && !defined(TOOLCHAIN_ARM_MICRO)
     #define STACK_SIZE 1536
+#elif (defined(TARGET_EFR32)) && !defined(TOOLCHAIN_ARM_MICRO)
+    #define STACK_SIZE 768
 #elif defined(TARGET_MCU_NRF51822) || defined(TARGET_MCU_NRF52832)
     #define STACK_SIZE 1024
 #elif defined(TARGET_XDOT_L151CC)
diff --git a/TESTS/mbedmicro-rtos-mbed/semaphore/main.cpp b/TESTS/mbedmicro-rtos-mbed/semaphore/main.cpp
index 5a08d57161..4960170b5b 100644
--- a/TESTS/mbedmicro-rtos-mbed/semaphore/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/semaphore/main.cpp
@@ -35,6 +35,8 @@
     #define STACK_SIZE 768
 #elif (defined(TARGET_EFM32GG_STK3700)) && !defined(TOOLCHAIN_ARM_MICRO)
     #define STACK_SIZE 1536
+#elif (defined(TARGET_EFR32)) && !defined(TOOLCHAIN_ARM_MICRO)
+    #define STACK_SIZE 768
 #elif defined(TARGET_MCU_NRF51822) || defined(TARGET_MCU_NRF52832)
     #define STACK_SIZE 768
 #elif defined(TARGET_XDOT_L151CC)
diff --git a/TESTS/mbedmicro-rtos-mbed/threads/main.cpp b/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
index f021ee8bd5..daf89d0300 100644
--- a/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
@@ -27,6 +27,8 @@
     #define STACK_SIZE 1024
 #elif defined(TARGET_HI2110)
     #define STACK_SIZE 512
+#elif defined(TARGET_EFR32)
+    #define STACK_SIZE 512
 #else
     #define STACK_SIZE DEFAULT_STACK_SIZE
 #endif