diff --git a/backends/cuda/runtime/cuda_backend.cpp b/backends/cuda/runtime/cuda_backend.cpp
index e10322ad40c..58ab54e1aac 100644
--- a/backends/cuda/runtime/cuda_backend.cpp
+++ b/backends/cuda/runtime/cuda_backend.cpp
@@ -26,9 +26,7 @@
 #include <executorch/backends/cuda/runtime/shims/memory.h>
 #include <executorch/backends/cuda/runtime/utils.h>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 #define LOAD_SYMBOL(name, handle)                                \
   do {                                                           \
@@ -335,14 +333,13 @@ class ET_EXPERIMENTAL CudaBackend final
   }
 };
 
-} // namespace cuda
+} // namespace executorch::backends::cuda
 
+namespace executorch::backends {
 namespace {
 auto cls = cuda::CudaBackend();
 executorch::runtime::Backend backend{"CudaBackend", &cls};
 static executorch::runtime::Error success_with_compiler =
     register_backend(backend);
 } // namespace
-
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends
diff --git a/backends/cuda/runtime/guard.cpp b/backends/cuda/runtime/guard.cpp
index 885efc7670d..674cc6387b3 100644
--- a/backends/cuda/runtime/guard.cpp
+++ b/backends/cuda/runtime/guard.cpp
@@ -9,9 +9,7 @@
 #include <executorch/backends/cuda/runtime/guard.h>
 #include <executorch/runtime/platform/log.h>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 namespace {
 // Thread-local stream storage (private to this file)
@@ -146,6 +144,4 @@ Result<CUDAStreamGuard> CUDAStreamGuard::create(
   return stream_guard;
 }
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/guard.h b/backends/cuda/runtime/guard.h
index 4e5a18a4c0f..3f187000f90 100644
--- a/backends/cuda/runtime/guard.h
+++ b/backends/cuda/runtime/guard.h
@@ -14,9 +14,7 @@
 #include <executorch/runtime/core/result.h>
 #include <cstdint>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 using executorch::runtime::Error;
 using executorch::runtime::Result;
@@ -190,6 +188,4 @@ class CUDAStreamGuard {
   DeviceIndex device_index_;
 };
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/cuda_guard.cpp b/backends/cuda/runtime/shims/cuda_guard.cpp
index 5740d0bf654..bb07acc7ffa 100644
--- a/backends/cuda/runtime/shims/cuda_guard.cpp
+++ b/backends/cuda/runtime/shims/cuda_guard.cpp
@@ -8,9 +8,7 @@
 
 #include <executorch/backends/cuda/runtime/shims/cuda_guard.h>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 extern "C" {
 
@@ -104,6 +102,4 @@ AOTITorchError aoti_torch_get_current_cuda_stream(
 
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/cuda_guard.h b/backends/cuda/runtime/shims/cuda_guard.h
index 6da869064a7..f930f3df643 100644
--- a/backends/cuda/runtime/shims/cuda_guard.h
+++ b/backends/cuda/runtime/shims/cuda_guard.h
@@ -13,9 +13,7 @@
 #include <executorch/backends/cuda/runtime/guard.h>
 #include <cstdint>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 using executorch::backends::aoti::AOTITorchError;
 
@@ -99,6 +97,4 @@ AOTITorchError aoti_torch_get_current_cuda_stream(
 
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/memory.cpp b/backends/cuda/runtime/shims/memory.cpp
index a054169330b..b8e3dc8e21b 100644
--- a/backends/cuda/runtime/shims/memory.cpp
+++ b/backends/cuda/runtime/shims/memory.cpp
@@ -19,9 +19,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 using executorch::aten::SizesType;
 using executorch::aten::StridesType;
@@ -659,6 +657,4 @@ AOTITorchError aoti_torch__reinterpret_tensor(
 
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/memory.h b/backends/cuda/runtime/shims/memory.h
index bcec6621285..7a8d4c3609b 100644
--- a/backends/cuda/runtime/shims/memory.h
+++ b/backends/cuda/runtime/shims/memory.h
@@ -12,9 +12,7 @@
 #include <executorch/backends/aoti/common_shims.h>
 #include <cstdint>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 using executorch::backends::aoti::AOTITorchError;
 using executorch::backends::aoti::Tensor;
@@ -145,6 +143,4 @@ aoti_torch_copy_(Tensor* self, Tensor* src, int32_t non_blocking);
 void clear_all_tensors();
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/tensor_attribute.cpp b/backends/cuda/runtime/shims/tensor_attribute.cpp
index 5b640b7a9e8..1a14c79f9f2 100644
--- a/backends/cuda/runtime/shims/tensor_attribute.cpp
+++ b/backends/cuda/runtime/shims/tensor_attribute.cpp
@@ -8,9 +8,7 @@
 
 #include <executorch/backends/cuda/runtime/shims/tensor_attribute.h>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 extern "C" {
 
@@ -31,6 +29,4 @@ int32_t aoti_torch_device_type_cuda() {
 
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/shims/tensor_attribute.h b/backends/cuda/runtime/shims/tensor_attribute.h
index e99958b4f0c..15a4e397d24 100644
--- a/backends/cuda/runtime/shims/tensor_attribute.h
+++ b/backends/cuda/runtime/shims/tensor_attribute.h
@@ -12,9 +12,7 @@
 #include <executorch/runtime/core/error.h>
 #include <cstdint>
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 // Common using declarations for ExecutorTorch types
 using executorch::runtime::Error;
@@ -35,6 +33,4 @@ int32_t aoti_torch_device_type_cuda();
 
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda
diff --git a/backends/cuda/runtime/utils.h b/backends/cuda/runtime/utils.h
index 02c3abfc83f..2d805724090 100644
--- a/backends/cuda/runtime/utils.h
+++ b/backends/cuda/runtime/utils.h
@@ -34,9 +34,7 @@
 #define ET_CUDA_KERNEL_LAUNCH_CHECK_OR_RETURN_ERROR() \
   ET_CUDA_CHECK_OR_RETURN_ERROR(cudaGetLastError())
 
-namespace executorch {
-namespace backends {
-namespace cuda {
+namespace executorch::backends::cuda {
 
 // Enum for supported data types in et-cuda backend
 enum class SupportedDTypes : int32_t {
@@ -125,6 +123,4 @@ inline AOTITorchError validate_dtype(int32_t dtype) {
 }
 } // extern "C"
 
-} // namespace cuda
-} // namespace backends
-} // namespace executorch
+} // namespace executorch::backends::cuda