diff --git a/bindings/php5/tests/Makefile.am b/bindings/php5/tests/Makefile.am
index b2d8549e..bb20cf01 100644
--- a/bindings/php5/tests/Makefile.am
+++ b/bindings/php5/tests/Makefile.am
@@ -1,6 +1,6 @@
 MAINTAINERCLEANFILES = Makefile.in
 if PHP5_ENABLED
-TESTS_ENVIRONMENT=env "SRCDIR=$(srcdir)/"
+TESTS_ENVIRONMENT=env "SRCDIR=$(srcdir)/" "PHP5=$(PHP5)"
 TESTS = profile_tests.sh binding_tests.sh
 endif
 
diff --git a/bindings/php5/tests/binding_tests.sh b/bindings/php5/tests/binding_tests.sh
index 3bfad5d6..0971ab2b 100755
--- a/bindings/php5/tests/binding_tests.sh
+++ b/bindings/php5/tests/binding_tests.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
 
-php5 -n -d extension_dir=../.libs -d extension=lasso.so ${SRCDIR}binding_tests.php
+${PHP5:?PHP5 variable is not defined} -n -d extension_dir=../.libs -d extension=lasso.so ${SRCDIR}binding_tests.php
diff --git a/bindings/php5/tests/profile_tests.sh b/bindings/php5/tests/profile_tests.sh
index 08a53fac..f7298079 100755
--- a/bindings/php5/tests/profile_tests.sh
+++ b/bindings/php5/tests/profile_tests.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
 
-php5 -n -d extension_dir=../.libs -d extension=lasso.so ${SRCDIR}profile_tests.php
+${PHP5:?PHP5 variable is not defined} -n -d extension_dir=../.libs -d extension=lasso.so ${SRCDIR}profile_tests.php