diff --git a/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix b/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix
new file mode 100644
index 000000000000..2b2f3464ecee
--- /dev/null
+++ b/pkgs/os-specific/linux/kernel/linux-rt-5.15.nix
@@ -0,0 +1,45 @@
+{ lib, buildLinux, fetchurl
+, kernelPatches ? [ ]
+, structuredExtraConfig ? {}
+, extraMeta ? {}
+, argsOverride ? {}
+, ... } @ args:
+
+let
+  version = "5.15.79-rt54"; # updated by ./update-rt.sh
+  branch = lib.versions.majorMinor version;
+  kversion = builtins.elemAt (lib.splitString "-" version) 0;
+in buildLinux (args // {
+  inherit version;
+
+  # modDirVersion needs a patch number, change X.Y-rtZ to X.Y.0-rtZ.
+  modDirVersion = if (builtins.match "[^.]*[.][^.]*-.*" version) == null then version
+    else lib.replaceStrings ["-"] [".0-"] version;
+
+  src = fetchurl {
+    url = "mirror://kernel/linux/kernel/v5.x/linux-${kversion}.tar.xz";
+    sha256 = "0m61k7k6lj24z9a266q08wzghggjik2wizcabdwd1vn0vcqr18yb";
+  };
+
+  kernelPatches = let rt-patch = {
+    name = "rt";
+    patch = fetchurl {
+      url = "mirror://kernel/linux/kernel/projects/rt/${branch}/older/patch-${version}.patch.xz";
+      sha256 = "098dml58d2nf7qhwn1pznqk7wvsh83rh85gsw7nmn2dym08510p9";
+    };
+  }; in [ rt-patch ] ++ kernelPatches;
+
+  structuredExtraConfig = with lib.kernel; {
+    PREEMPT_RT = yes;
+    # Fix error: unused option: PREEMPT_RT.
+    EXPERT = yes; # PREEMPT_RT depends on it (in kernel/Kconfig.preempt)
+    # Fix error: option not set correctly: PREEMPT_VOLUNTARY (wanted 'y', got 'n').
+    PREEMPT_VOLUNTARY = lib.mkForce no; # PREEMPT_RT deselects it.
+    # Fix error: unused option: RT_GROUP_SCHED.
+    RT_GROUP_SCHED = lib.mkForce (option no); # Removed by sched-disable-rt-group-sched-on-rt.patch.
+  } // structuredExtraConfig;
+
+  extraMeta = extraMeta // {
+    inherit branch;
+  };
+} // argsOverride)
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 749b9c2ba512..dcf616cdbcaf 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -822,6 +822,7 @@ mapAliases ({
 
   # Linux kernels
   linux-rt_5_10 = linuxKernel.kernels.linux_rt_5_10;
+  linux-rt_5_15 = linuxKernel.kernels.linux_rt_5_15;
   linux-rt_5_4 = linuxKernel.kernels.linux_rt_5_4;
   linuxPackages_4_14 = linuxKernel.packages.linux_4_14;
   linuxPackages_4_19 = linuxKernel.packages.linux_4_19;
@@ -841,6 +842,7 @@ mapAliases ({
   linuxPackages_rpi3 = linuxKernel.packages.linux_rpi3;
   linuxPackages_rpi4 = linuxKernel.packages.linux_rpi4;
   linuxPackages_rt_5_10 = linuxKernel.packages.linux_rt_5_10;
+  linuxPackages_rt_5_15 = linuxKernel.packages.linux_rt_5_15;
   linuxPackages_rt_5_4 = linuxKernel.packages.linux_rt_5_4;
   linux_4_14 = linuxKernel.kernels.linux_4_14;
   linux_4_19 = linuxKernel.kernels.linux_4_19;
diff --git a/pkgs/top-level/linux-kernels.nix b/pkgs/top-level/linux-kernels.nix
index 166f09f6e49a..53127bbd998d 100644
--- a/pkgs/top-level/linux-kernels.nix
+++ b/pkgs/top-level/linux-kernels.nix
@@ -151,6 +151,14 @@ in {
       ];
     };
 
+    linux_rt_5_15 = callPackage ../os-specific/linux/kernel/linux-rt-5.15.nix {
+      kernelPatches = [
+        kernelPatches.bridge_stp_helper
+        kernelPatches.request_key_helper
+        kernelPatches.export-rt-sched-migrate
+      ];
+    };
+
     linux_5_17 = throw "linux 5.17 was removed because it has reached its end of life upstream";
 
     linux_5_18 = throw "linux 5.18 was removed because it has reached its end of life upstream";
@@ -526,6 +534,7 @@ in {
      # realtime kernel packages
      linux_rt_5_4 = packagesFor kernels.linux_rt_5_4;
      linux_rt_5_10 = packagesFor kernels.linux_rt_5_10;
+     linux_rt_5_15 = packagesFor kernels.linux_rt_5_15;
   };
 
   rpiPackages = {