diff --git a/firefox.sh.in b/firefox.sh.in
index 2c7d5c0..06aadbe 100644
--- a/firefox.sh.in
+++ b/firefox.sh.in
@@ -144,9 +144,11 @@ GNOME_DISABLE_CRASH_DIALOG=1
 export GNOME_DISABLE_CRASH_DIALOG
 
 ##
-## Use /var/tmp instead of /tmp because of 1GB /tmp limit in  Fedora 18 and later
+## Use $MOZ_TMPDIR if set. Otherwise use /var/tmp instead of /tmp
+## because of 1GB /tmp limit in Fedora 18 and later.
+## See: https://bugzilla.redhat.com/show_bug.cgi?id=867073
 ##
-TMPDIR="/var/tmp"
+TMPDIR="${MOZ_TMPDIR:-/var/tmp}"
 export TMPDIR
 
 # OK, here's where all the real work gets done