diff --git a/src/php/bin/determine_extension_dir.sh b/src/php/bin/determine_extension_dir.sh
index 6bbd934bf13..1e042155501 100755
--- a/src/php/bin/determine_extension_dir.sh
+++ b/src/php/bin/determine_extension_dir.sh
@@ -27,12 +27,12 @@
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
 set -e
 default_extension_dir=$(php-config --extension-dir)
-if command -v brew >/dev/null && [ -d $(brew --prefix)/opt/grpc-php ]; then
-  # homebrew and the grpc-php formula are installed
-  extension_dir="-d extension_dir="$(brew --prefix)/opt/grpc-php
+if command -v brew > /dev/null && \
+   brew ls --versions | grep php5[5\|6]-grpc > /dev/null; then
+  # the grpc php extension was installed by homebrew
+  :
 elif [ ! -e $default_extension_dir/grpc.so ]; then
   # the grpc extension is not found in the default PHP extension dir
   # try the source modules directory
@@ -45,5 +45,5 @@ elif [ ! -e $default_extension_dir/grpc.so ]; then
   for f in $default_extension_dir/*.so; do
     ln -s $f $module_dir/$(basename $f) &> /dev/null || true
   done
-  extension_dir="-d extension_dir="$module_dir
+  extension_dir="-d extension_dir=${module_dir} -d extension=grpc.so"
 fi
diff --git a/src/php/bin/interop_client.sh b/src/php/bin/interop_client.sh
index 42e075cbe88..17b888dd4ed 100755
--- a/src/php/bin/interop_client.sh
+++ b/src/php/bin/interop_client.sh
@@ -31,5 +31,5 @@
 set -e
 cd $(dirname $0)
 source ./determine_extension_dir.sh
-php $extension_dir -d extension=grpc.so \
+php $extension_dir \
   ../tests/interop/interop_client.php $@ 1>&2
diff --git a/src/php/bin/run_gen_code_test.sh b/src/php/bin/run_gen_code_test.sh
index 03a9101a458..6e56c7207c2 100755
--- a/src/php/bin/run_gen_code_test.sh
+++ b/src/php/bin/run_gen_code_test.sh
@@ -31,8 +31,8 @@
 set -e
 cd $(dirname $0)
 source ./determine_extension_dir.sh
-export GRPC_TEST_HOST=localhost:7071
-php $extension_dir -d extension=grpc.so $(which phpunit) -v --debug --strict \
+export GRPC_TEST_HOST=localhost:50051
+php $extension_dir $(which phpunit) -v --debug --strict \
   ../tests/generated_code/GeneratedCodeTest.php
-php $extension_dir -d extension=grpc.so $(which phpunit) -v --debug --strict \
+php $extension_dir $(which phpunit) -v --debug --strict \
   ../tests/generated_code/GeneratedCodeWithCallbackTest.php
diff --git a/src/php/bin/run_tests.sh b/src/php/bin/run_tests.sh
index 4c37285455b..953f408ea8d 100755
--- a/src/php/bin/run_tests.sh
+++ b/src/php/bin/run_tests.sh
@@ -33,5 +33,5 @@
 set -e
 cd $(dirname $0)
 source ./determine_extension_dir.sh
-php $extension_dir -d extension=grpc.so $(which phpunit) -v --debug --strict \
+php $extension_dir $(which phpunit) -v --debug --strict \
   ../tests/unit_tests