diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index c206db9..7be0419 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -21,10 +21,11 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest, macos-15-intel]
         arch: [native]
-        python: ["{cp310,pp311}"]
+        python: ["{cp310,cp314t,cp315t,pp311}"]
         # Split aarch64 across jobs because it uses emulation (slow)
         include:
           # DNS fails inside i686 containers on ubuntu-26.04 runners
+          # cffi has no free-threaded i686 wheels
           - os: ubuntu-24.04
             arch: i686
             python: "{cp310,pp311}"
@@ -34,6 +35,9 @@ jobs:
           - os: ubuntu-latest
             arch: aarch64
             python: "pp311"
+          - os: ubuntu-latest
+            arch: aarch64
+            python: "{cp314t,cp315t}"
     steps:
       - uses: actions/checkout@v7
         with:
diff --git a/NEWS.rst b/NEWS.rst
index 4f957ca..b0da1d2 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -4,6 +4,12 @@ Version 0.1.8 -- unreleased
  * Fix possible crashes when a stream is garbage-collected while it is
    running, or when an action is garbage-collected after being cancelled
  * Update PortAudio submodule to the current development version
+ * Add wheels for free-threaded CPython 3.14t, and limited API wheels
+   (``abi3.abi3t``) for CPython 3.15 and 3.15t and newer
+ * Fix building from source on free-threaded CPython, which produced a
+   wheel wrongly tagged ``abi3`` that could not be installed
+ * Fix possible crashes when actions are started or waited for from
+   several threads at the same time
 
 Version 0.1.7 -- 2024-07-02 -- PyPI__ -- diff__
  * Restore the ``x86_64`` Linux wheels that were missing from 0.1.6
diff --git a/doc/api.rst b/doc/api.rst
index 202fd38..c29bd9a 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -36,6 +36,13 @@ Common parameters that are shared by most commands:
 
 All commands return a corresponding "action", which can be compared against the
 active `actions`, and can be used  as input for `cancel()` and `wait()`.
+The commands, `actions` and `wait()` can be used from several threads at
+once.  The methods inherited from `sounddevice.Stream` (e.g.
+:meth:`~sounddevice.Stream.start` and :meth:`~sounddevice.Stream.close`)
+cannot, so they must be called from one thread or synchronized by the user,
+as required by PortAudio.  Likewise, a `RingBuffer` that is used for playback
+(or recording) must only be written to (or read from) by one thread at a time.
+
 The fields of action objects are defined in C but can be accessed with
 Python (e.g. ``my_action.stats.min_blocksize``)
 *after* the command is finished:
diff --git a/setup.py b/setup.py
index 990cb5a..80eaff4 100644
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,7 @@
-from setuptools import setup, Extension
-from wheel.bdist_wheel import bdist_wheel
+import sys
+import sysconfig
+
+from setuptools import setup
 
 __version__ = 'unknown'
 
@@ -12,16 +14,15 @@
 
 # Adapted from
 # https://github.com/joerick/python-abi3-package-sample/blob/main/setup.py
-class bdist_wheel_abi3(bdist_wheel):
-    def get_tag(self):
-        python, abi, plat = super().get_tag()
-
-        if python.startswith("cp"):
-            # on CPython, our wheels are abi3 and compatible back to 3.2,
-            # but let's set it to our min version anyway
-            return "cp310", "abi3", plat
-
-        return python, abi, plat
+# On CPython our wheels are abi3. Free-threaded builds support the limited API
+# (as abi3t, PEP 803) only from 3.15 on, so 3.14t gets a version-specific
+# wheel.
+options = {}
+if sys.implementation.name == 'cpython':
+    if not sysconfig.get_config_var('Py_GIL_DISABLED'):
+        options['bdist_wheel'] = {'py_limited_api': 'cp310'}
+    elif sys.version_info >= (3, 15):
+        options['bdist_wheel'] = {'py_limited_api': 'cp315'}
 
 
 setup(
@@ -29,5 +30,5 @@ def get_tag(self):
     package_dir={'': 'src'},
     py_modules=['rtmixer'],
     cffi_modules=['rtmixer_build.py:ffibuilder'],  # sets Py_LIMITED_API for us
-    cmdclass={"bdist_wheel": bdist_wheel_abi3},
+    options=options,
 )
diff --git a/src/rtmixer.py b/src/rtmixer.py
index d481614..ba9dfaf 100644
--- a/src/rtmixer.py
+++ b/src/rtmixer.py
@@ -5,6 +5,8 @@
 """
 __version__ = '0.1.7'
 
+import threading as _threading
+
 import sounddevice as _sd
 from pa_ringbuffer import init as _init_ringbuffer
 from _rtmixer import ffi as _ffi, lib as _lib
@@ -40,6 +42,8 @@ def __init__(self, kind, qsize=16, **kwargs):
 
         self._actions = {}
         self._temp_action_ptr = _ffi.new('struct action**')
+        # The queues allow only one reader and one writer at a time:
+        self._lock = _threading.Lock()
 
     def __del__(self):
         # The C callback uses memory owned by this object, so the stream
@@ -53,8 +57,9 @@ def __del__(self):
     @property
     def actions(self):
         """The set of active "actions"."""
-        self._drain_result_q()
-        return self._actions.keys()
+        with self._lock:
+            self._drain_result_q()
+            return set(self._actions)
 
     @property
     def stats(self):
@@ -135,17 +140,22 @@ def _check_channels(self, channels, kind):
         return channels, mapping
 
     def _enqueue(self, action, keep_alive=None):
-        self._drain_result_q()
-        self._temp_action_ptr[0] = action
-        ret = self._action_q.write(self._temp_action_ptr)
-        if ret != 1:
-            raise RuntimeError(
-                'Action queue is full, consider increasing qsize')
-        assert action not in self._actions
-        self._actions[action] = keep_alive
+        with self._lock:
+            self._drain_result_q()
+            self._temp_action_ptr[0] = action
+            ret = self._action_q.write(self._temp_action_ptr)
+            if ret != 1:
+                raise RuntimeError(
+                    'Action queue is full, consider increasing qsize')
+            assert action not in self._actions
+            self._actions[action] = keep_alive
 
     def _drain_result_q(self):
-        """Get actions from the result queue and discard them."""
+        """Get actions from the result queue and discard them.
+
+        Must be called with ``self._lock`` held.
+
+        """
         while self._result_q.readinto(self._temp_action_ptr):
             # Each item is a linked list of actions
             action = self._temp_action_ptr[0]
diff --git a/tools/cibw_repair_wheel_command.sh b/tools/cibw_repair_wheel_command.sh
index fb26641..8896759 100755
--- a/tools/cibw_repair_wheel_command.sh
+++ b/tools/cibw_repair_wheel_command.sh
@@ -12,7 +12,3 @@ elif [[ "$RUNNER_OS" == "macOS" ]]; then
 else
     cp $WHEEL $DEST_DIR
 fi
-
-if [[ "$(python -c 'import platform; print(platform.python_implementation())')" == "CPython" ]]; then
-    pipx run abi3audit --strict --report $WHEEL
-fi