diff --git a/libcudacxx/include/cuda/std/__cccl/architecture.h b/libcudacxx/include/cuda/std/__cccl/architecture.h
index 1c7f25d6b0e..c50fe4fea1c 100644
--- a/libcudacxx/include/cuda/std/__cccl/architecture.h
+++ b/libcudacxx/include/cuda/std/__cccl/architecture.h
@@ -26,7 +26,9 @@
 #endif
 
 // X86 64-bit
-#if defined(_M_X64) || defined(__amd64__) || defined(__x86_64__)
+
+// _M_X64 is defined even if we are compiling in Arm64 emulation mode
+#if (defined(_M_X64) && !defined(_M_ARM64EC)) || defined(__amd64__) || defined(__x86_64__)
 #  define _CCCL_ARCH_X86_64_() 1
 #else
 #  define _CCCL_ARCH_X86_64_() 0