diff --git a/trick_source/sim_services/MemoryManager/test/Makefile b/trick_source/sim_services/MemoryManager/test/Makefile
index e3f455af..6537a7fc 100644
--- a/trick_source/sim_services/MemoryManager/test/Makefile
+++ b/trick_source/sim_services/MemoryManager/test/Makefile
@@ -15,7 +15,7 @@ TRICK_CPPFLAGS += -I$(GTEST_HOME)/include -I$(TRICK_HOME)/include -g -Wall -Wext
 
 TRICK_LIBS = -L${TRICK_LIB_DIR} -ltrick_mm -ltrick_units -ltrick -ltrick_mm -ltrick_units -ltrick
 
-TRICK_EXEC_LINK_LIBS += ${GTEST_HOME}/lib/libgtest.a ${GTEST_HOME}/lib/libgtest_main.a
+TRICK_EXEC_LINK_LIBS += ${GTEST_HOME}/lib/libgtest.a ${GTEST_HOME}/lib/libgtest_main.a -lpthread
 
 # All tests produced by this Makefile.  Remember to add new tests you
 # created to the list.