diff --git a/bin/pyenv-sh-activate b/bin/pyenv-sh-activate
index d6b0d35..38091ee 100755
--- a/bin/pyenv-sh-activate
+++ b/bin/pyenv-sh-activate
@@ -96,8 +96,8 @@ fi
 venv="${versions}"
 
 if [ -n "${VIRTUAL_ENV}" ]; then
-  # exit as success if some virtualenv is already activated outside from pyenv-virtualenv
-  if [ -z "${PYENV_VIRTUAL_ENV}" ]; then
+  # exit as success if a non-pyenv virtualenv is active
+  if [[ -z $PYENV_VIRTUAL_ENV || $PYENV_VIRTUAL_ENV != "$VIRTUAL_ENV" ]]; then
     if [ -z "${FORCE}" ]; then
       if [ -z "${QUIET}" ]; then
         echo "pyenv-virtualenv: virtualenv \`${VIRTUAL_ENV}' is already activated" 1>&2
diff --git a/test/activate.bats b/test/activate.bats
index 9c1fc67..8c1760a 100644
--- a/test/activate.bats
+++ b/test/activate.bats
@@ -439,6 +439,34 @@ EOS
   unstub pyenv-prefix
 }
 
+@test "do nothing if a 3rd-party virtualenv is active" {
+  export PYENV_VIRTUALENV_INIT=1
+  export VIRTUAL_ENV="${TMP}/venv-3rd-party"
+  unset PYENV_VIRTUAL_ENV
+
+  PYENV_SHELL="bash" run pyenv-sh-activate "venv"
+
+  assert_success
+  assert_output <<EOS
+pyenv-virtualenv: virtualenv \`${TMP}/venv-3rd-party' is already activated
+true
+EOS
+}
+
+@test "do nothing if a 3rd-party virtualenv is active over ours" {
+  export PYENV_VIRTUALENV_INIT=1
+  export VIRTUAL_ENV="${TMP}/venv-3rd-party"
+  export PYENV_VIRTUAL_ENV="${PYENV_ROOT}/versions/venv"
+
+  PYENV_SHELL="bash" run pyenv-sh-activate "venv"
+
+  assert_success
+  assert_output <<EOS
+pyenv-virtualenv: virtualenv \`${TMP}/venv-3rd-party' is already activated
+true
+EOS
+}
+
 @test "should fail if activate is invoked as a command" {
   run pyenv-activate