diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e8e1a2cf7..020a75f15 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -50,12 +50,20 @@ jobs:
           path: ./dist/tornado-*.tar.gz
 
   build_wheels:
-    name: Build wheels on ${{ matrix.os }}
+    name: Build wheels on ${{ matrix.os }}${{ matrix.name_suffix || '' }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-24.04, ubuntu-24.04-arm, windows-2025, windows-11-arm, macos-15]
+        include:
+          - os: ubuntu-24.04
+          - os: ubuntu-24.04-arm
+          - os: ubuntu-24.04
+            cibw_archs: "riscv64"
+            name_suffix: "-riscv64"
+          - os: windows-2025
+          - os: windows-11-arm
+          - os: macos-15
 
     steps:
       - uses: actions/checkout@v4
@@ -66,8 +74,18 @@ jobs:
         with:
           python-version: ${{ env.python-version }}
 
+      - name: Set up QEMU
+        if: matrix.cibw_archs == 'riscv64'
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: riscv64
+
       - name: Build wheels
-        uses: pypa/cibuildwheel@v3.1.3
+        uses: pypa/cibuildwheel@v3.3.0
+        env:
+          CIBW_ARCHS: ${{ matrix.cibw_archs || 'auto' }}
+          # Increase timeouts for RISC-V due to QEMU emulation slowness
+          CIBW_ENVIRONMENT: ${{ matrix.cibw_archs == 'riscv64' && 'ASYNC_TEST_TIMEOUT=30' || '' }}
 
       - name: Audit ABI3 compliance
         # This may be moved into cibuildwheel itself in the future. See
@@ -76,7 +94,7 @@ jobs:
 
       - uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.os }}
+          name: artifacts-${{ matrix.os }}${{ matrix.name_suffix || '' }}
           path: ./wheelhouse/*.whl
 
   upload_pypi_test:
diff --git a/tornado/test/httputil_test.py b/tornado/test/httputil_test.py
index 7a46b9115..3629898db 100644
--- a/tornado/test/httputil_test.py
+++ b/tornado/test/httputil_test.py
@@ -18,6 +18,7 @@
 import datetime
 import logging
 import pickle
+import platform
 import time
 import urllib.parse
 import unittest
@@ -648,6 +649,7 @@ def test_unquote(self):
                 c = parse_cookie(encoded)
                 self.assertEqual(c["a"], decoded)
 
+    @unittest.skipIf(platform.machine() == "riscv64", "Performance test unreliable under QEMU emulation")
     def test_unquote_large(self):
         # Adapted from
         # https://github.com/python/cpython/blob/dc7a2b6522ec7af41282bc34f405bee9b306d611/Lib/test/test_http_cookies.py#L87
diff --git a/tornado/test/simple_httpclient_test.py b/tornado/test/simple_httpclient_test.py
index 9b21acada..102738ad6 100644
--- a/tornado/test/simple_httpclient_test.py
+++ b/tornado/test/simple_httpclient_test.py
@@ -3,11 +3,13 @@
 import errno
 import logging
 import os
+import platform
 import re
 import socket
 import ssl
 import sys
 import typing  # noqa: F401
+import unittest
 
 from tornado.escape import to_unicode, utf8
 from tornado import gen, version
@@ -315,6 +317,7 @@ async def resolve(self, *args, **kwargs):
         cleanup_event.set()
         yield gen.sleep(0.2)
 
+    @unittest.skipIf(platform.machine() == "riscv64", "Test has race conditions under QEMU emulation")
     def test_request_timeout(self):
         timeout = 0.1
         if os.name == "nt":