diff --git a/tests/test_posix_semaphore/Makefile b/tests/test_posix_semaphore/Makefile
index 8bd82b2903..3940ad0eb9 100644
--- a/tests/test_posix_semaphore/Makefile
+++ b/tests/test_posix_semaphore/Makefile
@@ -1,6 +1,11 @@
 export PROJECT = test_posix_semaphore
 include ../Makefile.tests_common
 
+BOARD_BLACKLIST := mbed_lpc1768 redbee-econotag chronos
+# mbed_lpc1768: not enough RAM
+# redbee-econotag: not enough RAM
+# chronos: not enough RAM
+
 USEMODULE += posix
 
 DISABLE_MODULE += auto_init