diff --git a/bypy/sources.json b/bypy/sources.json
index f10212c5a8..8c700aaf30 100644
--- a/bypy/sources.json
+++ b/bypy/sources.json
@@ -1160,7 +1160,6 @@
     {
         "name": "onnx",
 		"comment": "This is newer than the version needed for the version of piper-phonemize to get it to build on macOS (see CMakeLists.txt in piper-phonemize)",
-		"os": "linux,macos",
         "unix": {
             "filename": "onnx-1.19.0.tar.gz",
             "hash": "sha256:dd945b2fb8c2e7df7243e9d96c0293f45350058f0f713f66c519834a49a6c99d",
@@ -1170,7 +1169,6 @@
     {
         "name": "piper-espeak",
 		"comment": "This is the version needed for the version of piper-phonemize we use (see CMakeLists.txt in piper-phonemize)",
-		"os": "linux,macos",
         "unix": {
             "filename": "espeak-1.zip",
             "hash": "sha256:150fc955926a084a77ebe25c9e8287bde2e2a17bbf9b23a25c147b556837949f",
@@ -1180,7 +1178,6 @@
     {
         "name": "piper-phonemize",
 		"comment": "This is the version needed for the version of piper we use (see CMakeLists.txt in piper)",
-		"os": "linux,macos",
         "unix": {
             "filename": "piper-phonemize-1.zip",
             "hash": "sha256:cc57a4a00a0f5bd50555a93c94c0622da065a2a90b9c896bfbe8b45519e2e9c2",
@@ -1189,7 +1186,6 @@
     },
     {
         "name": "piper",
-		"os": "linux,macos",
         "unix": {
             "filename": "piper-2023.11.14.tar.gz",
             "hash": "sha256:8b684e102cfe23af097830db9555a8641f17735725853c531a1daeb34b6ed1a8",
diff --git a/bypy/windows/__main__.py b/bypy/windows/__main__.py
index d73a27a6bc..2a4c91dc0a 100644
--- a/bypy/windows/__main__.py
+++ b/bypy/windows/__main__.py
@@ -18,6 +18,7 @@ import zipfile
 from bypy.constants import CL, LINK, MT, PREFIX, RC, SIGNTOOL, SW, build_dir, python_major_minor_version, worker_env
 from bypy.constants import SRC as CALIBRE_DIR
 from bypy.freeze import cleanup_site_packages, extract_extension_modules, freeze_python, path_to_freeze_dir
+from bypy.pkgs.piper import copy_piper_dir
 from bypy.utils import mkdtemp, py_compile, run, walk
 
 iv = globals()['init_env']
@@ -140,6 +141,7 @@ def freeze(env, ext_dir, incdir):
         copybin(f, ossm)
     for f in glob.glob(os.path.join(PREFIX, 'ffmpeg', 'bin', '*.dll')):
         copybin(f)
+    copy_piper_dir(PREFIX, env.dll_dir)
 
     copybin(os.path.join(env.python_base, 'python%s.dll' % env.py_ver.replace('.', '')))
     copybin(os.path.join(env.python_base, 'python%s.dll' % env.py_ver[0]))
diff --git a/src/calibre/test_build.py b/src/calibre/test_build.py
index c3f0c16d71..08f680b0fd 100644
--- a/src/calibre/test_build.py
+++ b/src/calibre/test_build.py
@@ -123,7 +123,6 @@ class BuildTest(unittest.TestCase):
         from speechd.client import SSIPClient
         del SSIPClient
 
-    @unittest.skipIf(iswindows, 'Piper not available on windows')
     def test_piper(self):
         import subprocess