diff --git a/pkgs/development/python-modules/deep-ep/default.nix b/pkgs/development/python-modules/deep-ep/default.nix
new file mode 100644
index 000000000000..a26eafdd22e9
--- /dev/null
+++ b/pkgs/development/python-modules/deep-ep/default.nix
@@ -0,0 +1,114 @@
+{
+  lib,
+  buildPythonPackage,
+  fetchFromGitHub,
+
+  # build-system
+  torch,
+  setuptools,
+
+  # env
+  symlinkJoin,
+  cudaPackages,
+
+  # buildInputs
+  pybind11,
+  rdma-core,
+
+  config,
+  cudaCapabilities ? torch.cudaCapabilities,
+  cudaSupport ? config.cudaSupport,
+}:
+let
+  inherit (lib)
+    getBin
+    getInclude
+    ;
+
+  minSupportedCudaCapability = "8.0"; # build fails with 7.5
+
+  minCudaCapability = builtins.head (
+    builtins.sort (a: b: builtins.compareVersions a b < 0) cudaCapabilities
+  );
+
+  cudaCapabilities' =
+    if lib.versionOlder minCudaCapability minSupportedCudaCapability then
+      throw ''
+        CUDA capability "${minCudaCapability}" from `cudaCapabilities` is incompatible with DeepEP.
+        Only CUDA capabilities must be "${minSupportedCudaCapability}" or newer.
+        Build `python3Packages.deep-ep` with a compatible `cudaCapabilities` list.
+      ''
+    else
+      cudaCapabilities;
+
+  disableSm90Features = lib.versionOlder minCudaCapability "9.0";
+in
+buildPythonPackage.override { inherit (torch) stdenv; } (finalAttrs: {
+  pname = "deep-ep";
+  version = "1.2.1";
+  pyproject = true;
+
+  src = fetchFromGitHub {
+    owner = "deepseek-ai";
+    repo = "DeepEP";
+    tag = "v${finalAttrs.version}";
+    hash = "sha256-xURR3uBAwKjDTNEG9p/vRRhH4Ldiz/u6kD/a+DPn5/Q=";
+  };
+
+  build-system = [
+    setuptools
+    torch
+  ];
+
+  env = lib.optionalAttrs cudaSupport (
+    {
+      TORCH_CUDA_ARCH_LIST = "${lib.concatStringsSep " " cudaCapabilities'}";
+
+      DISABLE_SM90_FEATURES =
+        if disableSm90Features then
+          lib.warn ''
+            python3Packages.deepep: Disabling SM90 features as the provided `cudaCapabilities` list include '${minCudaCapability}'
+          '' "1"
+        else
+          "0";
+
+      CUDA_HOME = symlinkJoin {
+        name = "cuda-redist";
+        paths = with cudaPackages; [
+          (getBin cuda_nvcc)
+
+          (getInclude cuda_cccl) # <nv/target>
+          (getInclude cuda_cudart) # cuda_runtime.h
+          (getInclude libcublas) # cublas_v2.h
+          (getInclude libcusolver) # cusolverDn.h
+          (getInclude libcusparse) # cusparse.h
+        ];
+      };
+    }
+
+    # nvshmem must be disabled (unsetting NVSHMEM_DIR) when supporting <9.0 capabilities
+    # https://github.com/deepseek-ai/DeepEP/blob/v1.2.1/setup.py#L65
+    // lib.optionalAttrs (!disableSm90Features) {
+      NVSHMEM_DIR = (getInclude cudaPackages.libnvshmem).outPath;
+    }
+  );
+
+  buildInputs = [
+    pybind11
+    rdma-core
+  ];
+
+  pythonImportsCheck = [ "deep_ep" ];
+
+  # Tests check internode communications which is not possible in the sandbox
+  doCheck = false;
+
+  meta = {
+    description = "Efficient expert-parallel communication library";
+    homepage = "https://github.com/deepseek-ai/DeepEP";
+    changelog = "https://github.com/deepseek-ai/DeepEP/releases/tag/${finalAttrs.src.tag}";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ GaetanLepage ];
+    broken = !cudaSupport;
+  };
+})
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 115f36295c15..fc5a11fe7acb 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -3756,6 +3756,8 @@ self: super: with self; {
 
   deep-chainmap = callPackage ../development/python-modules/deep-chainmap { };
 
+  deep-ep = callPackage ../development/python-modules/deep-ep { };
+
   deep-translator = callPackage ../development/python-modules/deep-translator { };
 
   deepdiff = callPackage ../development/python-modules/deepdiff { };