diff --git a/Lib/test/test_wave.py b/Lib/test/test_wave.py
index 4c21f16553775c..e77f026d1df916 100644
--- a/Lib/test/test_wave.py
+++ b/Lib/test/test_wave.py
@@ -207,6 +207,30 @@ def test_open_in_write_raises(self):
             support.gc_collect()
             self.assertIsNone(cm.unraisable)
 
+    def test_write_odd_data_chunk_pads_and_updates_riff_size(self):
+        # gh-117716: odd-sized data chunks must be padded with one zero byte.
+        with io.BytesIO() as output:
+            with wave.open(output, mode='wb') as w:
+                w.setnchannels(1)
+                w.setsampwidth(1)
+                w.setframerate(48000)
+                w.writeframes(b'\x80')
+
+            value = output.getvalue()
+
+        self.assertEqual(value[-1], 0)
+        self.assertEqual(
+            int.from_bytes(value[4:8], byteorder='little'),
+            38,
+        )
+
+        with wave.open(io.BytesIO(value), mode='rb') as r:
+            self.assertEqual(r.getnchannels(), 1)
+            self.assertEqual(r.getsampwidth(), 1)
+            self.assertEqual(r.getframerate(), 48000)
+            self.assertEqual(r.getnframes(), 1)
+            self.assertEqual(r.readframes(-1), b'\x80')
+
 
 class WaveOpen(unittest.TestCase):
     def test_open_pathlike(self):
diff --git a/Lib/wave.py b/Lib/wave.py
index 25ca9ef168e8a5..2a26f8d3b3663a 100644
--- a/Lib/wave.py
+++ b/Lib/wave.py
@@ -565,6 +565,8 @@ def close(self):
         try:
             if self._file:
                 self._ensure_header_written(0)
+                if self._datawritten & 1:
+                    self._file.write(b'\x00')
                 if self._datalength != self._datawritten:
                     self._patchheader()
                 self._file.flush()
@@ -600,7 +602,7 @@ def _write_header(self, initlength):
         except (AttributeError, OSError):
             self._form_length_pos = None
         self._file.write(struct.pack('<L4s4sLHHLLHH4s',
-            36 + self._datalength, b'WAVE', b'fmt ', 16,
+            36 + self._datalength + (self._datalength & 1), b'WAVE', b'fmt ', 16,
             WAVE_FORMAT_PCM, self._nchannels, self._framerate,
             self._nchannels * self._framerate * self._sampwidth,
             self._nchannels * self._sampwidth,
@@ -616,7 +618,7 @@ def _patchheader(self):
             return
         curpos = self._file.tell()
         self._file.seek(self._form_length_pos, 0)
-        self._file.write(struct.pack('<L', 36 + self._datawritten))
+        self._file.write(struct.pack('<L', 36 + self._datawritten + (self._datawritten & 1)))
         self._file.seek(self._data_length_pos, 0)
         self._file.write(struct.pack('<L', self._datawritten))
         self._file.seek(curpos, 0)
diff --git a/Misc/NEWS.d/next/Library/2026-02-25-22-20-00.gh-issue-117716.w6kYp9.rst b/Misc/NEWS.d/next/Library/2026-02-25-22-20-00.gh-issue-117716.w6kYp9.rst
new file mode 100644
index 00000000000000..77182a3f2c3303
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-02-25-22-20-00.gh-issue-117716.w6kYp9.rst
@@ -0,0 +1 @@
+Fix :mod:`wave` writing of odd-sized ``data`` chunks by appending the required RIFF pad byte and correcting the RIFF chunk size field accordingly.