diff --git a/.mailmap b/.mailmap
index 0ebf887509..ecc03b71b9 100644
--- a/.mailmap
+++ b/.mailmap
@@ -12,31 +12,32 @@
 #     # shows raw names/emails, filtered by mapped name:
 #   $ git log --format='%an %ae' --author=$NAME | uniq -c
 
-acrefoot <acrefoot@zulip.com> <acrefoot@humbughq.com>
-acrefoot <acrefoot@zulip.com> <acrefoot@dropbox.com>
 acrefoot <acrefoot@zulip.com> <acrefoot@alum.mit.edu>
-Adam Benesh <Adam.Benesh@gmail.com> <Adam-Daniel.Benesh@t-systems.com>
+acrefoot <acrefoot@zulip.com> <acrefoot@dropbox.com>
+acrefoot <acrefoot@zulip.com> <acrefoot@humbughq.com>
 Adam Benesh <Adam.Benesh@gmail.com>
+Adam Benesh <Adam.Benesh@gmail.com> <Adam-Daniel.Benesh@t-systems.com>
 Adarsh Tiwari <xoldyckk@gmail.com>
 Alex Vandiver <alexmv@zulip.com> <alex@chmrr.net>
 Alex Vandiver <alexmv@zulip.com> <github@chmrr.net>
 Allen Rabinovich <allenrabinovich@yahoo.com> <allenr@humbughq.com>
 Allen Rabinovich <allenrabinovich@yahoo.com> <allenr@zulip.com>
 Alya Abbott <alya@zulip.com> <2090066+alya@users.noreply.github.com>
-Aman Agrawal <amanagr@zulip.com> <f2016561@pilani.bits-pilani.ac.in>
+Alya Abbott <alya@zulip.com> <alyaabbott@elance-odesk.com>
 Aman Agrawal <amanagr@zulip.com>
+Aman Agrawal <amanagr@zulip.com> <f2016561@pilani.bits-pilani.ac.in>
 Anders Kaseorg <anders@zulip.com> <anders@zulipchat.com>
 Anders Kaseorg <anders@zulip.com> <andersk@mit.edu>
-Aryan Shridhar <aryanshridhar7@gmail.com> <53977614+aryanshridhar@users.noreply.github.com>
-Aryan Shridhar <aryanshridhar7@gmail.com>
 aparna-bhatt <aparnabhatt2001@gmail.com> <86338542+aparna-bhatt@users.noreply.github.com>
+Aryan Shridhar <aryanshridhar7@gmail.com>
+Aryan Shridhar <aryanshridhar7@gmail.com> <53977614+aryanshridhar@users.noreply.github.com>
 Ashwat Kumar Singh <ashwat.kumarsingh.met20@itbhu.ac.in>
 Austin Riba <austin@zulip.com> <austin@m51.io>
 BIKI DAS <bikid475@gmail.com>
 Brijmohan Siyag <brijsiyag@gmail.com>
 Brock Whittaker <brock@zulipchat.com> <bjwhitta@asu.edu>
-Brock Whittaker <brock@zulipchat.com> <brockwhittaker@Brocks-MacBook.local>
 Brock Whittaker <brock@zulipchat.com> <brock@zulipchat.org>
+Brock Whittaker <brock@zulipchat.com> <brockwhittaker@Brocks-MacBook.local>
 Chris Bobbe <cbobbe@zulip.com> <cbobbe@zulipchat.com>
 Chris Bobbe <cbobbe@zulip.com> <csbobbe@gmail.com>
 Danny Su <contact@dannysu.com> <opensource@emailengine.org>
@@ -59,19 +60,21 @@ Jeff Arnold <jbarnold@gmail.com> <jbarnold@humbughq.com>
 Jeff Arnold <jbarnold@gmail.com> <jbarnold@zulip.com>
 Jessica McKellar <jesstess@mit.edu> <jesstess@humbughq.com>
 Jessica McKellar <jesstess@mit.edu> <jesstess@zulip.com>
+Joseph Ho <josephho678@gmail.com>
+Joseph Ho <josephho678@gmail.com> <62449508+Joelute@users.noreply.github.com>
 Julia Bichler <julia.bichler@tum.de> <74348920+juliaBichler01@users.noreply.github.com>
 Karl Stolley <karl@zulip.com> <karl@stolley.dev>
 Kevin Mehall <km@kevinmehall.net> <kevin@humbughq.com>
 Kevin Mehall <km@kevinmehall.net> <kevin@zulip.com>
 Kevin Scott <kevin.scott.98@gmail.com>
 Lalit Kumar Singh <lalitkumarsingh3716@gmail.com>
-Lauryn Menard <lauryn@zulip.com> <lauryn.menard@gmail.com>
 Lauryn Menard <lauryn@zulip.com> <63245456+laurynmm@users.noreply.github.com>
+Lauryn Menard <lauryn@zulip.com> <lauryn.menard@gmail.com>
+m-e-l-u-h-a-n <purushottam.tiwari.cd.cse19@itbhu.ac.in>
+m-e-l-u-h-a-n <purushottam.tiwari.cd.cse19@itbhu.ac.in> <pururshottam.tiwari.cd.cse19@itbhu.ac.in>
 Mateusz Mandera <mateusz.mandera@zulip.com> <mateusz.mandera@protonmail.com>
 Matt Keller <matt@zulip.com>
 Matt Keller <matt@zulip.com> <m@cognusion.com>
-m-e-l-u-h-a-n <purushottam.tiwari.cd.cse19@itbhu.ac.in>
-m-e-l-u-h-a-n <purushottam.tiwari.cd.cse19@itbhu.ac.in> <pururshottam.tiwari.cd.cse19@itbhu.ac.in>
 Noble Mittal <noblemittal@outlook.com> <62551163+beingnoble03@users.noreply.github.com>
 nzai <nzaih18@gmail.com> <70953556+nzaih1999@users.noreply.github.com>
 Palash Baderia <palash.baderia@outlook.com>
@@ -82,10 +85,10 @@ Priyam Seth <sethpriyam1@gmail.com> <b19188@students.iitmandi.ac.in>
 Ray Kraesig <rkraesig@zulip.com> <rkraesig@zulipchat.com>
 Reid Barton <rwbarton@gmail.com> <rwbarton@humbughq.com>
 Rein Zustand (rht) <rhtbot@protonmail.com>
+Rishabh Maheshwari <b20063@students.iitmandi.ac.in>
 Rishi Gupta <rishig@zulipchat.com> <rishig+git@mit.edu>
 Rishi Gupta <rishig@zulipchat.com> <rishig@kandralabs.com>
 Rishi Gupta <rishig@zulipchat.com> <rishig@users.noreply.github.com>
-Rishabh Maheshwari <b20063@students.iitmandi.ac.in>
 Rixant Rokaha <rixantrokaha@gmail.com>
 Rixant Rokaha <rixantrokaha@gmail.com> <rishantrokaha@gmail.com>
 Rixant Rokaha <rixantrokaha@gmail.com> <rrokaha@caldwell.edu>
@@ -109,24 +112,21 @@ Tim Abbott <tabbott@zulip.com> <tabbott@humbughq.com>
 Tim Abbott <tabbott@zulip.com> <tabbott@mit.edu>
 Tim Abbott <tabbott@zulip.com> <tabbott@zulipchat.com>
 Ujjawal Modi <umodi2003@gmail.com> <99073049+Ujjawal3@users.noreply.github.com>
-Vishnu KS <vishnu@zulip.com> <hackerkid@vishnuks.com>
-Vishnu KS <vishnu@zulip.com> <yo@vishnuks.com>
-Alya Abbott <alya@zulip.com> <alyaabbott@elance-odesk.com>
 umkay <ukhan@zulipchat.com> <umaimah.k@gmail.com>
 umkay <ukhan@zulipchat.com> <umkay@users.noreply.github.com>
-Waseem Daher <wdaher@zulip.com> <wdaher@humbughq.com>
+Vishnu KS <vishnu@zulip.com> <hackerkid@vishnuks.com>
+Vishnu KS <vishnu@zulip.com> <yo@vishnuks.com>
 Waseem Daher <wdaher@zulip.com> <wdaher@dropbox.com>
-Yash RE <33805964+YashRE42@users.noreply.github.com> <YashRE42@github.com>
+Waseem Daher <wdaher@zulip.com> <wdaher@humbughq.com>
 Yash RE <33805964+YashRE42@users.noreply.github.com>
+Yash RE <33805964+YashRE42@users.noreply.github.com> <YashRE42@github.com>
 Yogesh Sirsat <yogeshsirsat56@gmail.com>
 Yogesh Sirsat <yogeshsirsat56@gmail.com> <41695888+yogesh-sirsat@users.noreply.github.com>
-Zeeshan Equbal <equbalzeeshan@gmail.com> <54993043+zee-bit@users.noreply.github.com>
 Zeeshan Equbal <equbalzeeshan@gmail.com>
+Zeeshan Equbal <equbalzeeshan@gmail.com> <54993043+zee-bit@users.noreply.github.com>
 Zev Benjamin <zev@zulip.com> <zev@dropbox.com>
 Zev Benjamin <zev@zulip.com> <zev@humbughq.com>
 Zev Benjamin <zev@zulip.com> <zev@mit.edu>
 Zixuan James Li <p359101898@gmail.com>
-Zixuan James Li <p359101898@gmail.com> <39874143+PIG208@users.noreply.github.com>
 Zixuan James Li <p359101898@gmail.com> <359101898@qq.com>
-Joseph Ho <josephho678@gmail.com>
-Joseph Ho <josephho678@gmail.com> <62449508+Joelute@users.noreply.github.com>
+Zixuan James Li <p359101898@gmail.com> <39874143+PIG208@users.noreply.github.com>
diff --git a/tools/lint b/tools/lint
index 70545206aa..2fc707ed91 100755
--- a/tools/lint
+++ b/tools/lint
@@ -194,6 +194,11 @@ def run() -> None:
         description="Syntactic grep (semgrep) code search tool (config: ./tools/semgrep.yml)",
     )
 
+    linter_config.external_linter(
+        "mailmap",
+        ["sh", "-c", "grep '^[^#]' .mailmap | LC_ALL=C.UTF-8 sort -cf"],
+        description="Check that .mailmap is sorted",
+    )
     linter_config.external_linter(
         "thirdparty",
         ["tools/check-thirdparty"],