diff --git a/puppet/zulip/templates/postfix/main.cf.erb b/puppet/zulip/templates/postfix/main.cf.erb
index fed7e94b51..5257ab1430 100644
--- a/puppet/zulip/templates/postfix/main.cf.erb
+++ b/puppet/zulip/templates/postfix/main.cf.erb
@@ -38,3 +38,6 @@ virtual_alias_maps = regexp:/etc/postfix/virtual
 allow_percent_hack = no
 allow_untrusted_routing = yes
 strict_rfc821_envelopes = no
+
+# Ingest messages up to 25MB
+message_size_limit = 26214400