diff --git a/nixos/modules/services/misc/gitlab.nix b/nixos/modules/services/misc/gitlab.nix
index db62d6f90901..6619949f5540 100644
--- a/nixos/modules/services/misc/gitlab.nix
+++ b/nixos/modules/services/misc/gitlab.nix
@@ -901,6 +901,16 @@ in {
         '';
       };
 
+      sidekiq.concurrency = mkOption {
+        type = with types; nullOr int;
+        default = null;
+        description = lib.mdDoc ''
+          How many processor threads to use for processing sidekiq background job queues. When null, the GitLab default is used.
+
+          See <https://docs.gitlab.com/ee/administration/sidekiq/extra_sidekiq_processes.html#manage-thread-counts-explicitly> for details.
+        '';
+      };
+
       sidekiq.memoryKiller.enable = mkOption {
         type = types.bool;
         default = true;
@@ -1454,12 +1464,17 @@ in {
         TimeoutSec = "infinity";
         Restart = "always";
         WorkingDirectory = "${cfg.packages.gitlab}/share/gitlab";
-        ExecStart = utils.escapeSystemdExecArgs [
-          "${cfg.packages.gitlab}/share/gitlab/bin/sidekiq-cluster"
-          "-e" "production"
-          "-r" "."
-          "*" # all queue groups
-        ];
+        ExecStart = utils.escapeSystemdExecArgs (
+          [
+            "${cfg.packages.gitlab}/share/gitlab/bin/sidekiq-cluster"
+            "*" # all queue groups
+          ] ++ lib.optionals (cfg.sidekiq.concurrency != null) [
+            "--concurrency" (toString cfg.sidekiq.concurrency)
+          ] ++ [
+            "--environment" "production"
+            "--require" "."
+          ]
+        );
       };
     };