diff --git a/Library/Homebrew/extend/os/mac/hardware/cpu.rb b/Library/Homebrew/extend/os/mac/hardware/cpu.rb
index 35fe32d116..8f2c80c03a 100644
--- a/Library/Homebrew/extend/os/mac/hardware/cpu.rb
+++ b/Library/Homebrew/extend/os/mac/hardware/cpu.rb
@@ -127,6 +127,8 @@ module Hardware
           :arm_lobos
         when 0x72015832             # ARMv8.6-A (M3 Max, Palma)
           :arm_palma
+        when 0x6f5129ac             # ARMv9.2-A (M4, Donan)
+          :arm_donan
         else
           # When adding new ARM CPU families, please also update
           # test/hardware/cpu_spec.rb to include the new families.
diff --git a/Library/Homebrew/test/hardware/cpu_spec.rb b/Library/Homebrew/test/hardware/cpu_spec.rb
index 093b579eef..8786d4bc95 100644
--- a/Library/Homebrew/test/hardware/cpu_spec.rb
+++ b/Library/Homebrew/test/hardware/cpu_spec.rb
@@ -29,6 +29,7 @@ RSpec.describe Hardware::CPU do
         :amd_k12,
         :arm,
         :arm_blizzard_avalanche,
+        :arm_donan,
         :arm_firestorm_icestorm,
         :arm_hurricane_zephyr,
         :arm_ibiza,