diff --git a/pkgs/applications/networking/mailreaders/thunderbird/packages.nix b/pkgs/applications/networking/mailreaders/thunderbird/packages.nix
index c9cc9f901a33..e373c443ea57 100644
--- a/pkgs/applications/networking/mailreaders/thunderbird/packages.nix
+++ b/pkgs/applications/networking/mailreaders/thunderbird/packages.nix
@@ -10,12 +10,12 @@ in
 rec {
   thunderbird = common rec {
     pname = "thunderbird";
-    version = "91.5.0";
+    version = "91.5.1";
     application = "comm/mail";
     binaryName = pname;
     src = fetchurl {
       url = "mirror://mozilla/thunderbird/releases/${version}/source/thunderbird-${version}.source.tar.xz";
-      sha512 = "e1cafbd99e67e8fef346e936890a22aeadded4aa8be604607535ae933251bc1b2a3b56c2b62045b3d37ecb09999adb746157df188d1a32dfe75685f3af959b7d";
+      sha512 = "5939e09b143e440efa906d95cda06826bd3a73b2edde5eed86229b8a0e4d1434519059f37d319d26978d7eea9b3906c5e1c1543a2bc2465625d5ab5438855717";
     };
     patches = [
       # The file to be patched is different from firefox's `no-buildconfig-ffx90.patch`.