diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2a0ba72c5..2e267c233 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,6 +43,8 @@ if(BUILD_TESTING)
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_pr_overlap.py)
         add_test(NAME progress_report COMMAND ${Python3_EXECUTABLE}
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_progress.py)
+        add_test(NAME progress_encoding COMMAND ${Python3_EXECUTABLE}
+            ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_progress_encoding.py)
         add_test(NAME import_audit COMMAND ${Python3_EXECUTABLE}
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_import_audit.py)
         add_test(NAME conventions_function_bodies COMMAND ${Python3_EXECUTABLE}
diff --git a/tools/progress.py b/tools/progress.py
index dc566a69a..808f35a39 100644
--- a/tools/progress.py
+++ b/tools/progress.py
@@ -2,6 +2,7 @@ import argparse
 import json
 import os
 import re
+import sys
 from html import escape
 from pathlib import Path
 
@@ -333,6 +334,8 @@ def report(base, head):
 
 
 if __name__ == "__main__":
+    if hasattr(sys.stdout, "reconfigure"):
+        sys.stdout.reconfigure(encoding="utf-8")
     parser = argparse.ArgumentParser()
     parser.add_argument("output", type=Path, nargs="?")
     parser.add_argument("--root", type=Path, help="source tree to measure instead of the one containing this script")
@@ -340,7 +343,7 @@ if __name__ == "__main__":
                         help="print a markdown report of the changes between two progress.json files")
     args = parser.parse_args()
     if args.compare:
-        base, head = (json.loads(path.read_text()) for path in args.compare)
+        base, head = (json.loads(path.read_text(encoding="utf-8")) for path in args.compare)
         print(report(base, head), end="")
         raise SystemExit
     if not args.output:
diff --git a/tools/tests/test_progress_encoding.py b/tools/tests/test_progress_encoding.py
new file mode 100644
index 000000000..289389fc5
--- /dev/null
+++ b/tools/tests/test_progress_encoding.py
@@ -0,0 +1,62 @@
+import json
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+PROGRESS = Path(__file__).resolve().parents[1] / "progress.py"
+
+
+def snapshot(implemented, library="libSceExample"):
+    return {
+        "libraries": {
+            "done": int(implemented), "total": 1, "percent": 100 if implemented else 0,
+            "groups": [{"name": library, "done": int(implemented), "todo": int(not implemented),
+                        "done_names": ["Ready"] if implemented else [],
+                        "todo_names": [] if implemented else ["Ready"]}],
+        },
+        "shaders": {"done": 0, "total": 0, "percent": 0, "groups": []},
+    }
+
+
+class ProgressEncodingTests(unittest.TestCase):
+    def compare(self, base, head, encoding="cp1252"):
+        with tempfile.TemporaryDirectory(prefix="progress encoding ") as directory:
+            paths = [Path(directory) / name for name in ("base.json", "head.json")]
+            for path, data in zip(paths, (base, head)):
+                path.write_text(json.dumps(data, ensure_ascii=False), encoding="utf-8")
+            env = {**os.environ, "PYTHONIOENCODING": encoding, "PYTHONUTF8": "0"}
+            result = subprocess.run([sys.executable, "-X", "utf8=0", str(PROGRESS), "--compare", *map(str, paths)],
+                                    env=env, capture_output=True, timeout=10)
+        self.assertEqual(result.returncode, 0, result.stderr.decode("utf-8", errors="replace"))
+        return result.stdout.decode("utf-8").replace("\r\n", "\n")
+
+    def test_implemented_report_with_cp1252_stdout(self):
+        report = self.compare(snapshot(False), snapshot(True))
+        self.assertIn("\U0001f4c8 **System libraries**: 100%", report)
+        self.assertIn("\u2705 1 implemented", report)
+        self.assertIn("| libSceExample | `Ready` |", report)
+
+    def test_regression_report_with_cp1252_stdout(self):
+        report = self.compare(snapshot(True), snapshot(False))
+        self.assertIn("\U0001f4c9 **System libraries**: 0%", report)
+        self.assertIn("\u26a0\ufe0f 1 went back to stubs", report)
+        self.assertIn("-1 reverted", report)
+
+    def test_utf8_snapshot_names_are_preserved(self):
+        library = "libSce\u6e2c\u8a66\U0001f3ae"
+        report = self.compare(snapshot(False, library), snapshot(True, library))
+        self.assertIn(f"| {library} | `Ready` |", report)
+
+    def test_unchanged_snapshots_produce_no_output(self):
+        self.assertEqual(self.compare(snapshot(False), snapshot(False)), "")
+
+    def test_utf8_stdout_report_is_unchanged(self):
+        base, head = snapshot(False), snapshot(True)
+        self.assertEqual(self.compare(base, head, "utf-8"), self.compare(base, head))
+
+
+if __name__ == "__main__":
+    unittest.main()