diff --git a/setup.py b/setup.py
index 54ea4c8..e2a94e9 100644
--- a/setup.py
+++ b/setup.py
@@ -2,6 +2,7 @@
 
 import platform
 import sys
+import sysconfig
 
 from setuptools import setup
 
@@ -14,7 +15,11 @@
 
         class BDistWheel(wheel.bdist_wheel.bdist_wheel):
             def finalize_options(self):
-                self.py_limited_api = f"cp3{sys.version_info[1]}"
+                # free-threaded CPython doesn't support limited API
+                if sysconfig.get_config_var("Py_GIL_DISABLED"):
+                    self.py_limited_api = False
+                else:
+                    self.py_limited_api = f"cp3{sys.version_info[1]}"
                 wheel.bdist_wheel.bdist_wheel.finalize_options(self)
 
         cmdclass["bdist_wheel"] = BDistWheel
diff --git a/src/_argon2_cffi_bindings/_ffi_build.py b/src/_argon2_cffi_bindings/_ffi_build.py
index 0d4d0be..cea7c14 100644
--- a/src/_argon2_cffi_bindings/_ffi_build.py
+++ b/src/_argon2_cffi_bindings/_ffi_build.py
@@ -2,6 +2,7 @@
 
 import os
 import platform
+import sysconfig
 
 from pathlib import Path
 
@@ -48,6 +49,7 @@ def _get_target_platform(arch_flags, default):
         "_ffi",
         "#include <argon2.h>",
         libraries=["argon2"],
+        py_limited_api=not sysconfig.get_config_var("Py_GIL_DISABLED"),
     )
 else:
     lib_base = Path("extras") / "libargon2" / "src"
@@ -56,6 +58,7 @@ def _get_target_platform(arch_flags, default):
         "#include <argon2.h>",
         extra_compile_args=["-msse2"] if (optimized and not windows) else None,
         include_dirs=[os.path.join("extras", "libargon2", "include")],
+        py_limited_api=not sysconfig.get_config_var("Py_GIL_DISABLED"),
         sources=[
             str(lib_base / path)
             for path in [