diff --git a/TESTS/mbedmicro-rtos-mbed/threads/main.cpp b/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
index 24438409331..1fb638b3cd9 100644
--- a/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/threads/main.cpp
@@ -10,6 +10,17 @@
   #error [NOT_SUPPORTED] test not supported
 #endif
 
+/*
+ * The stack size is defined in cmsis_os.h mainly dependent on the underlying toolchain and
+ * the C standard library. For GCC, ARM_STD and IAR it is defined with a size of 2048 bytes
+ * and for ARM_MICRO 512. Because of reduce RAM size some targets need a reduced stacksize.
+ */
+#if defined(TARGET_MCU_NRF51822) || defined(TARGET_MCU_NRF52832)
+    #define STACK_SIZE 512
+#else
+    #define STACK_SIZE DEFAULT_STACK_SIZE
+#endif
+
 using namespace utest::v1;
 
 // The counter type used accross all the tests
@@ -32,7 +43,7 @@ void increment_with_wait(counter_t* counter) {
 }
 
 void increment_with_child(counter_t* counter) {
-    Thread child(counter, increment);
+    Thread child(counter, increment, osPriorityNormal, STACK_SIZE);
     child.join();
 }
 
@@ -41,7 +52,7 @@ void increment_with_murder(counter_t* counter) {
         // take ownership of the counter mutex so it prevent the child to
         // modify counter.
         LockGuard lock(counter->internal_mutex());
-        Thread child(counter, increment);
+        Thread child(counter, increment, osPriorityNormal, STACK_SIZE);
         child.terminate();
     }
 
@@ -52,7 +63,7 @@ void increment_with_murder(counter_t* counter) {
 template <void (*F)(counter_t *)>
 void test_single_thread() {
     counter_t counter(0);
-    Thread thread(&counter, F);
+    Thread thread(&counter, F, osPriorityNormal, STACK_SIZE);
     thread.join();
     TEST_ASSERT_EQUAL(counter, 1);
 }
@@ -63,7 +74,7 @@ void test_parallel_threads() {
     Thread *threads[N];
 
     for (int i = 0; i < N; i++) {
-        threads[i] = new Thread(&counter, F);
+        threads[i] = new Thread(&counter, F, osPriorityNormal, STACK_SIZE);
     }
 
     for (int i = 0; i < N; i++) {
@@ -79,7 +90,7 @@ void test_serial_threads() {
     counter_t counter(0);
 
     for (int i = 0; i < N; i++) {
-        Thread thread(&counter, F);
+        Thread thread(&counter, F, osPriorityNormal, STACK_SIZE);
         thread.join();
     }