diff --git a/pythonfmu3/osutil.py b/pythonfmu3/osutil.py
index 568350e..6052eed 100644
--- a/pythonfmu3/osutil.py
+++ b/pythonfmu3/osutil.py
@@ -1,14 +1,40 @@
+import platform
 import sys
 
-import platform
+# FMI 3.0 platform tuples are "<arch>-<sys>" (FMI 3.0 standard, section 2.5.1.4),
+# e.g. x86_64-linux, aarch64-darwin, x86-windows.
+_SYSTEMS = {"Windows": "windows", "Linux": "linux", "Darwin": "darwin"}
+
+_ARCHITECTURES_64 = {
+    "x86_64": "x86_64", "amd64": "x86_64", "x64": "x86_64",
+    "i386": "x86_64", "i686": "x86_64", "x86": "x86_64",  # 64-bit Python on x86 hardware
+    "aarch64": "aarch64", "arm64": "aarch64", "armv8l": "aarch64",
+    "ppc64": "ppc64", "ppc64le": "ppc64",
+    "riscv64": "riscv64",
+}
+
+_ARCHITECTURES_32 = {
+    "x86_64": "x86", "amd64": "x86", "x64": "x86", "i386": "x86", "i686": "x86", "x86": "x86",
+    "aarch64": "aarch32", "arm64": "aarch32", "armv7l": "aarch32", "armv8l": "aarch32", "arm": "aarch32",
+    "ppc": "ppc32",
+    "riscv32": "riscv32",
+}
+
+
+def _is_64bit() -> bool:
+    # Bitness of the running interpreter, which is what the FMU binary must match
+    # (e.g. a 32-bit Python on 64-bit Windows needs x86-windows).
+    return sys.maxsize > 2 ** 32
+
+
+def get_fmu_arch() -> str:
+    """FMI 3.0 platform tuple of the running interpreter, e.g. 'aarch64-darwin'."""
+    machine = platform.machine().lower()
+    table = _ARCHITECTURES_64 if _is_64bit() else _ARCHITECTURES_32
+    arch = table.get(machine, machine or "unknown")
+    system = _SYSTEMS.get(platform.system(), platform.system().lower() or "unknown")
+    return f"{arch}-{system}"
 
-def get_fmu_arch():
-    #is_64bits = sys.maxsize > 2 ** 32
-    system = platform.system()
-    is_x86 = platform.machine() in ["i386", "AMD64", "x86_64"]
-    platforms = {"Windows": "windows", "Linux": "linux", "Darwin": "darwin"}
-    arch = "x86_64" if is_x86 else "x86"
-    return arch + "-" + platforms.get(system, "unknown")
 
 def get_platform() -> str:
     """Get FMU binary platform folder name."""
@@ -19,4 +45,3 @@ def get_lib_extension() -> str:
     """Get FMU library platform extension."""
     platforms = {"Darwin": "dylib", "Linux": "so", "Windows": "dll"}
     return platforms.get(platform.system(), "")
-
diff --git a/pythonfmu3/pythonfmu-export/CMakeLists.txt b/pythonfmu3/pythonfmu-export/CMakeLists.txt
index 8b48b84..8f68295 100644
--- a/pythonfmu3/pythonfmu-export/CMakeLists.txt
+++ b/pythonfmu3/pythonfmu-export/CMakeLists.txt
@@ -48,12 +48,44 @@ else ()
   set(TARGET_PLATFORM linux)
 endif ()
 
-if ("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
-  set(TARGET_PLATFORM x86_64-${TARGET_PLATFORM})
+# FMI 3.0 platform tuple <arch>-<sys>; must match pythonfmu3/osutil.py:get_fmu_arch().
+# The architecture is the one being *built for*: the Visual Studio -A option, or a single
+# CMAKE_OSX_ARCHITECTURES entry on macOS, take precedence over the host processor.
+if (CMAKE_GENERATOR_PLATFORM)
+  set(_arch "${CMAKE_GENERATOR_PLATFORM}")
+elseif (APPLE AND CMAKE_OSX_ARCHITECTURES)
+  list(LENGTH CMAKE_OSX_ARCHITECTURES _n_arch)
+  if (NOT _n_arch EQUAL 1)
+    message(FATAL_ERROR "Universal builds are not supported: set CMAKE_OSX_ARCHITECTURES to a single architecture")
+  endif ()
+  set(_arch "${CMAKE_OSX_ARCHITECTURES}")
+else ()
+  set(_arch "${CMAKE_SYSTEM_PROCESSOR}")
+endif ()
+string(TOLOWER "${_arch}" _arch)
+
+if (_arch MATCHES "^(aarch64|arm64|armv8)")
+  set(_fmi_arch aarch64)
+elseif (_arch MATCHES "^arm")
+  set(_fmi_arch aarch32)
+elseif (_arch MATCHES "^(x86_64|amd64|x64|i[3-6]86|x86|win32)$")
+  set(_fmi_arch x86)
 else ()
-  set(TARGET_PLATFORM x86-${TARGET_PLATFORM})
+  set(_fmi_arch "${_arch}")
 endif ()
 
+if ("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
+  if (_fmi_arch STREQUAL "x86")
+    set(_fmi_arch x86_64)
+  elseif (_fmi_arch STREQUAL "aarch32")
+    set(_fmi_arch aarch64)
+  endif ()
+elseif (_fmi_arch STREQUAL "aarch64")
+  set(_fmi_arch aarch32)
+endif ()
+
+set(TARGET_PLATFORM ${_fmi_arch}-${TARGET_PLATFORM})
+
 message("Building pythonfmu-export for platform ${TARGET_PLATFORM}")
 
 add_subdirectory(src)
diff --git a/pythonfmu3/tests/test_osutil.py b/pythonfmu3/tests/test_osutil.py
new file mode 100644
index 0000000..9dcd5bc
--- /dev/null
+++ b/pythonfmu3/tests/test_osutil.py
@@ -0,0 +1,23 @@
+import pytest
+
+from pythonfmu3 import osutil
+
+
+@pytest.mark.parametrize(
+    "system, machine, is_64bit, expected",
+    [
+        ("Darwin", "arm64", True, "aarch64-darwin"),     # Apple Silicon
+        ("Darwin", "x86_64", True, "x86_64-darwin"),     # Intel Mac (or Rosetta)
+        ("Linux", "x86_64", True, "x86_64-linux"),
+        ("Linux", "aarch64", True, "aarch64-linux"),     # Raspberry Pi 4/5, Graviton
+        ("Linux", "armv7l", False, "aarch32-linux"),
+        ("Windows", "AMD64", True, "x86_64-windows"),
+        ("Windows", "AMD64", False, "x86-windows"),      # 32-bit Python on 64-bit Windows
+        ("Windows", "ARM64", True, "aarch64-windows"),
+    ],
+)
+def test_fmi3_platform_tuple(monkeypatch, system, machine, is_64bit, expected):
+    monkeypatch.setattr(osutil.platform, "system", lambda: system)
+    monkeypatch.setattr(osutil.platform, "machine", lambda: machine)
+    monkeypatch.setattr(osutil, "_is_64bit", lambda: is_64bit)
+    assert osutil.get_platform() == expected