diff --git a/bin/brew b/bin/brew
index 402b438a25..02c0697c10 100755
--- a/bin/brew
+++ b/bin/brew
@@ -88,7 +88,7 @@ then
   PATH="/usr/bin:/bin:/usr/sbin:/sbin"
 
   FILTERED_ENV=()
-  for VAR in HOME SHELL PATH TERM LOGNAME USER CI TRAVIS http_proxy \
+  for VAR in HOME SHELL PATH TERM LOGNAME USER CI TRAVIS SUDO_ASKPASS http_proxy \
              "${!HOMEBREW_@}" "${!TRAVIS_@}" "${!JENKINS_@}"
   do
     # Skip if variable value is empty.