diff --git a/scripts/create_testenv.sh b/scripts/create_testenv.sh
index 736e164c05..29c5e7f568 100755
--- a/scripts/create_testenv.sh
+++ b/scripts/create_testenv.sh
@@ -4,9 +4,11 @@ set -e # fail on first error
 
 PYTHON_VERSION=${PYTHON_VERSION:-3.5} # if no python specified, use 3.5
 
-conda create -n testenv --yes pip python=${PYTHON_VERSION}
-
-source activate testenv
+if [[ "$*" != *--global* ]]
+then
+  conda create -n testenv --yes pip python=${PYTHON_VERSION}
+  source activate testenv
+fi
 
 conda install --yes pyqt=4.11.4 jupyter pyzmq numpy scipy nose matplotlib pandas Cython patsy statsmodels joblib coverage
 if [ ${PYTHON_VERSION} == "2.7" ]; then