diff --git a/BUILD.bazel b/BUILD.bazel
index 31384214..24cb9e08 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -2,7 +2,7 @@
 
 load("@bazel_skylib//lib:selects.bzl", "selects")
 load("//:bazel/platforms.bzl", "PLATFORM_CPU_ARM", "PLATFORM_CPU_ARM64", "PLATFORM_CPU_MIPS", "PLATFORM_CPU_PPC", "PLATFORM_CPU_RISCV32", "PLATFORM_CPU_RISCV64", "PLATFORM_CPU_X86_64")
-load("//:bazel/platforms.bzl", "PLATFORM_OS_MACOS", "PLATFORM_OS_LINUX", "PLATFORM_OS_FREEBSD", "PLATFORM_OS_ANDROID")
+load("//:bazel/platforms.bzl", "PLATFORM_OS_MACOS", "PLATFORM_OS_LINUX", "PLATFORM_OS_FREEBSD", "PLATFORM_OS_OPENBSD", "PLATFORM_OS_ANDROID")
 
 package(
     default_visibility = ["//visibility:public"],
@@ -170,13 +170,14 @@ cc_library(
     name = "hwcaps",
     srcs = [
         "src/hwcaps.c",
-        "src/hwcaps_freebsd.c",
+        "src/hwcaps_freebsd_or_openbsd.c",
         "src/hwcaps_linux_or_android.c",
     ],
     copts = C99_FLAGS,
     defines = selects.with_or({
         PLATFORM_OS_MACOS: ["HAVE_DLFCN_H"],
         PLATFORM_OS_FREEBSD: ["HAVE_STRONG_ELF_AUX_INFO"],
+        PLATFORM_OS_OPENBSD: ["HAVE_STRONG_ELF_AUX_INFO"],
         PLATFORM_OS_LINUX: ["HAVE_STRONG_GETAUXVAL"],
         PLATFORM_OS_ANDROID: ["HAVE_STRONG_GETAUXVAL"],
         "//conditions:default": [],
@@ -195,7 +196,7 @@ cc_library(
     testonly = 1,
     srcs = [
         "src/hwcaps.c",
-        "src/hwcaps_freebsd.c",
+        "src/hwcaps_freebsd_or_openbsd.c",
         "src/hwcaps_linux_or_android.c",
         "test/hwcaps_for_testing.cc",
     ],
@@ -230,7 +231,7 @@ cc_library(
             "src/impl_aarch64_linux_or_android.c",
             "src/impl_aarch64_macos_or_iphone.c",
             "src/impl_aarch64_windows.c",
-            "src/impl_aarch64_freebsd.c",
+            "src/impl_aarch64_freebsd_or_openbsd.c",
         ],
         PLATFORM_CPU_MIPS: ["src/impl_mips_linux_or_android.c"],
         PLATFORM_CPU_PPC: ["src/impl_ppc_linux.c"],
@@ -295,7 +296,7 @@ cc_library(
             "src/impl_aarch64_linux_or_android.c",
             "src/impl_aarch64_macos_or_iphone.c",
             "src/impl_aarch64_windows.c",
-            "src/impl_aarch64_freebsd.c",
+            "src/impl_aarch64_freebsd_or_openbsd.c",
         ],
         PLATFORM_CPU_MIPS: ["src/impl_mips_linux_or_android.c"],
         PLATFORM_CPU_PPC: ["src/impl_ppc_linux.c"],
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 18925e09..ca3269b9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -148,7 +148,7 @@ if(UNIX)
   add_library(unix_based_hardware_detection OBJECT
     ${PROJECT_SOURCE_DIR}/include/internal/hwcaps.h
     ${PROJECT_SOURCE_DIR}/src/hwcaps_linux_or_android.c
-    ${PROJECT_SOURCE_DIR}/src/hwcaps_freebsd.c
+    ${PROJECT_SOURCE_DIR}/src/hwcaps_freebsd_or_openbsd.c
     ${PROJECT_SOURCE_DIR}/src/hwcaps.c
   )
   setup_include_and_definitions(unix_based_hardware_detection)
diff --git a/bazel/platforms.bzl b/bazel/platforms.bzl
index 7ced3d1d..65d9a803 100644
--- a/bazel/platforms.bzl
+++ b/bazel/platforms.bzl
@@ -22,3 +22,5 @@ PLATFORM_OS_LINUX = ("@platforms//os:linux")
 PLATFORM_OS_ANDROID = ("@platforms//os:android")
 
 PLATFORM_OS_FREEBSD = ("@platforms//os:freebsd")
+
+PLATFORM_OS_OPENBSD = ("@platforms//os:openbsd")
diff --git a/include/cpu_features_macros.h b/include/cpu_features_macros.h
index 2d43b790..d61ec102 100644
--- a/include/cpu_features_macros.h
+++ b/include/cpu_features_macros.h
@@ -95,6 +95,10 @@
 #define CPU_FEATURES_OS_FREEBSD
 #endif
 
+#if defined(__OpenBSD__)
+#define CPU_FEATURES_OS_OPENBSD
+#endif
+
 #if defined(__ANDROID__)
 #define CPU_FEATURES_OS_ANDROID
 #endif
diff --git a/src/hwcaps_freebsd.c b/src/hwcaps_freebsd_or_openbsd.c
similarity index 89%
rename from src/hwcaps_freebsd.c
rename to src/hwcaps_freebsd_or_openbsd.c
index eb227504..db90297c 100644
--- a/src/hwcaps_freebsd.c
+++ b/src/hwcaps_freebsd_or_openbsd.c
@@ -14,7 +14,7 @@
 
 #include "cpu_features_macros.h"
 
-#ifdef CPU_FEATURES_OS_FREEBSD
+#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
 
 #include "internal/hwcaps.h"
 
@@ -47,8 +47,8 @@ const char *CpuFeatures_GetPlatformPointer(void) { return NULL; }
 const char *CpuFeatures_GetBasePlatformPointer(void) { return NULL; }
 
 #else
-#error "FreeBSD needs support for elf_aux_info"
+#error "FreeBSD / OpenBSD needs support for elf_aux_info"
 #endif  // HAVE_STRONG_ELF_AUX_INFO
 
 #endif  // CPU_FEATURES_TEST
-#endif  // CPU_FEATURES_OS_FREEBSD
+#endif  // CPU_FEATURES_OS_FREEBSD || CPU_FEATURES_OS_OPENBSD
diff --git a/src/impl_aarch64_cpuid.c b/src/impl_aarch64_cpuid.c
index 1ca56cd4..d2e08277 100644
--- a/src/impl_aarch64_cpuid.c
+++ b/src/impl_aarch64_cpuid.c
@@ -15,8 +15,8 @@
 #include "cpu_features_macros.h"
 
 #ifdef CPU_FEATURES_ARCH_AARCH64
-#if (defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX) || \
-     defined(CPU_FEATURES_OS_ANDROID))
+#if (defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD) || \
+     defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_ANDROID))
 #if (defined(CPU_FEATURES_COMPILER_GCC) || defined(CPU_FEATURES_COMPILER_CLANG))
 
 #include "internal/cpuid_aarch64.h"
@@ -35,6 +35,6 @@ uint64_t GetMidrEl1(void) {
 #error "Unsupported compiler, aarch64 cpuid requires either GCC or Clang."
 #endif  // (defined(CPU_FEATURES_COMPILER_GCC) ||
         // defined(CPU_FEATURES_COMPILER_CLANG))
-#endif  // (defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX)
-        // || defined(CPU_FEATURES_OS_ANDROID))
+#endif  // (defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
+        // || defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_ANDROID))
 #endif  // CPU_FEATURES_ARCH_AARCH64
diff --git a/src/impl_aarch64_freebsd.c b/src/impl_aarch64_freebsd_or_openbsd.c
similarity index 91%
rename from src/impl_aarch64_freebsd.c
rename to src/impl_aarch64_freebsd_or_openbsd.c
index d1696408..49e662a6 100644
--- a/src/impl_aarch64_freebsd.c
+++ b/src/impl_aarch64_freebsd_or_openbsd.c
@@ -15,7 +15,7 @@
 #include "cpu_features_macros.h"
 
 #ifdef CPU_FEATURES_ARCH_AARCH64
-#ifdef CPU_FEATURES_OS_FREEBSD
+#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
 
 #include "cpuinfo_aarch64.h"
 #include "impl_aarch64__base_implementation.inl"
@@ -42,5 +42,5 @@ Aarch64Info GetAarch64Info(void) {
   return info;
 }
 
-#endif  // CPU_FEATURES_OS_FREEBSD
+#endif  // CPU_FEATURES_OS_FREEBSD || CPU_FEATURES_OS_OPENBSD
 #endif  // CPU_FEATURES_ARCH_AARCH64
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index d2177f22..e317233e 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -25,7 +25,7 @@ target_link_libraries(stack_line_reader_for_test string_view filesystem_for_test
 add_library(all_libraries
         ../src/hwcaps.c
         ../src/hwcaps_linux_or_android.c
-        ../src/hwcaps_freebsd.c
+        ../src/hwcaps_freebsd_or_openbsd.c
         ../src/stack_line_reader.c)
 target_link_libraries(all_libraries hwcaps_for_testing stack_line_reader string_view)
 
@@ -81,7 +81,7 @@ if(PROCESSOR_IS_AARCH64)
     ../src/impl_aarch64_linux_or_android.c
     ../src/impl_aarch64_windows.c
     ../src/impl_aarch64_macos_or_iphone.c
-    ../src/impl_aarch64_freebsd.c
+    ../src/impl_aarch64_freebsd_or_openbsd.c
   )
   if(APPLE)
     target_compile_definitions(cpuinfo_aarch64_test PUBLIC CPU_FEATURES_MOCK_SYSCTL_AARCH64)
diff --git a/test/cpuinfo_aarch64_test.cc b/test/cpuinfo_aarch64_test.cc
index f1f55943..a84e6b6c 100644
--- a/test/cpuinfo_aarch64_test.cc
+++ b/test/cpuinfo_aarch64_test.cc
@@ -22,13 +22,13 @@
 #if defined(CPU_FEATURES_OS_WINDOWS)
 #include "internal/windows_utils.h"
 #endif  // CPU_FEATURES_OS_WINDOWS
-#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX)
+#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD) || defined(CPU_FEATURES_OS_LINUX)
 #include "internal/cpuid_aarch64.h"
-#endif  // defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX)
+#endif  // defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD) || defined(CPU_FEATURES_OS_LINUX)
 
 namespace cpu_features {
 class FakeCpuAarch64 {
-#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX)
+#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD) || defined(CPU_FEATURES_OS_LINUX)
  public:
   uint64_t GetMidrEl1() const { return _midr_el1; }
 
@@ -89,7 +89,7 @@ static FakeCpuAarch64& cpu() {
 }
 
 // Define OS dependent mock functions
-#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_LINUX)
+#if defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD) || defined(CPU_FEATURES_OS_LINUX)
 extern "C" uint64_t GetMidrEl1(void) { return cpu().GetMidrEl1(); }
 #elif defined(CPU_FEATURES_OS_MACOS)
 extern "C" bool GetDarwinSysCtlByName(const char* name) {
@@ -137,7 +137,7 @@ TEST_F(CpuidAarch64Test, Aarch64FeaturesEnum) {
 }
 
 // AT_HWCAP tests
-#if defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_FREEBSD)
+#if defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
 TEST_F(CpuidAarch64Test, FromHardwareCap) {
   ResetHwcaps();
   SetHardwareCapabilities(AARCH64_HWCAP_FP | AARCH64_HWCAP_AES, 0);
@@ -205,7 +205,7 @@ TEST_F(CpuidAarch64Test, FromHardwareCap2) {
   EXPECT_FALSE(info.features.dgh);
   EXPECT_FALSE(info.features.rng);
 }
-#endif  // defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_FREEBSD)
+#endif  // defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
 
 // OS dependent tests
 #if defined(CPU_FEATURES_OS_LINUX)
@@ -415,7 +415,7 @@ TEST_F(CpuidAarch64Test, WINDOWS_AARCH64_RPI4) {
   EXPECT_FALSE(info.features.jscvt);
   EXPECT_FALSE(info.features.lrcpc);
 }
-#elif defined(CPU_FEATURES_OS_FREEBSD)
+#elif defined(CPU_FEATURES_OS_FREEBSD) || defined(CPU_FEATURES_OS_OPENBSD)
 TEST_F(CpuidAarch64Test, MrsMidrEl1_RPI4) {
   ResetHwcaps();
   SetHardwareCapabilities(AARCH64_HWCAP_FP | AARCH64_HWCAP_CPUID, 0);