diff --git a/sample/Makefile b/sample/Makefile
index c6ca7568..d51b1545 100644
--- a/sample/Makefile
+++ b/sample/Makefile
@@ -4,6 +4,7 @@
 
 COMMON=-O2 -I../include -L../lib -std=c++17 -pthread -Wl,-no-as-needed -Wl,-rpath,'$$ORIGIN'/../lib
 
+.PHONY: all
 all:
 	$(CXX) $(COMMON) testxml.cc            -lmujoco          -o ../bin/testxml
 	$(CXX) $(COMMON) testspeed.cc          -lmujoco          -o ../bin/testspeed