diff --git a/libexec/pyenv b/libexec/pyenv
index 05955aa7..e294f638 100755
--- a/libexec/pyenv
+++ b/libexec/pyenv
@@ -18,6 +18,8 @@ if [ -z "$READLINK" ]; then
   exit 1
 fi
 
+unset GREP_OPTIONS
+
 resolve_link() {
   $READLINK "$1"
 }
diff --git a/test/libexec/pyenv-grep b/test/libexec/pyenv-grep
new file mode 100755
index 00000000..862c66fc
--- /dev/null
+++ b/test/libexec/pyenv-grep
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+grep -E "$@"
diff --git a/test/pyenv.bats b/test/pyenv.bats
index 2b33d9fc..759794ee 100644
--- a/test/pyenv.bats
+++ b/test/pyenv.bats
@@ -45,3 +45,11 @@ load test_helper
   assert_failure
   assert_output "pyenv: cannot change working directory to \`$dir'"
 }
+
+@test "conflicting GREP_OPTIONS" {
+  file="${BATS_TMPDIR}/hello"
+  echo "hello" > "$file"
+  GREP_OPTIONS="-F" run pyenv grep "hell." "$file"
+  assert_success
+  assert_output "hello"
+}