diff --git a/frigate/api/export.py b/frigate/api/export.py
index 27f85a2cde..6a4a6d5041 100644
--- a/frigate/api/export.py
+++ b/frigate/api/export.py
@@ -9,6 +9,7 @@ import zipfile
 from collections import deque
 from collections.abc import Iterator
 from pathlib import Path
+from urllib.parse import quote
 
 import psutil
 from fastapi import APIRouter, Depends, Query, Request
@@ -453,6 +454,22 @@ def _stream_case_archive(exports: list[Export]) -> Iterator[bytes]:
     yield from buffer.drain()
 
 
+def _content_disposition(filename: str, ascii_fallback: str) -> str:
+    """Build an attachment Content-Disposition that survives non-ASCII names.
+
+    Header values are encoded as latin-1, so a name outside that range cannot
+    go in filename at all. RFC 6266 handles this with a pair: a plain ASCII
+    filename for old clients, plus a percent-encoded UTF-8 filename* that
+    every current browser prefers.
+    """
+    ascii_name = filename if filename.isascii() else ascii_fallback
+
+    return (
+        f'attachment; filename="{ascii_name}"; '
+        f"filename*=UTF-8''{quote(filename, safe='')}"
+    )
+
+
 @router.get(
     "/cases/{case_id}/download",
     dependencies=[Depends(allow_any_authenticated())],
@@ -495,7 +512,9 @@ def download_export_case(
         _stream_case_archive(exports),
         media_type="application/zip",
         headers={
-            "Content-Disposition": f'attachment; filename="{archive_base}.zip"',
+            "Content-Disposition": _content_disposition(
+                f"{archive_base}.zip", f"{case_id}.zip"
+            ),
         },
     )
 
diff --git a/frigate/test/http_api/test_http_export.py b/frigate/test/http_api/test_http_export.py
index e0ceec559a..44eb0c2c4a 100644
--- a/frigate/test/http_api/test_http_export.py
+++ b/frigate/test/http_api/test_http_export.py
@@ -1,5 +1,7 @@
+import io
 import os
 import tempfile
+import zipfile
 from unittest.mock import patch
 
 from frigate.jobs.export import (
@@ -1431,3 +1433,79 @@ class TestHttpExport(BaseTestHttp):
             )
 
         assert response.status_code == 403
+
+    def test_download_export_case_with_multibyte_name(self):
+        """A case name outside latin-1 must not break the response headers."""
+        case = ExportCase.create(
+            id="case_multibyte",
+            name="テスト事案",
+            description="",
+            created_at=10,
+            updated_at=10,
+        )
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            video_path = os.path.join(tmpdir, "multibyte_export.mp4")
+            with open(video_path, "wb") as handle:
+                handle.write(b"video")
+
+            Export.create(
+                id="export_multibyte",
+                camera="front_door",
+                name="現場カメラ",
+                date=100,
+                video_path=video_path,
+                thumb_path=os.path.join(tmpdir, "multibyte_export.webp"),
+                in_progress=False,
+                export_case=case,
+            )
+
+            with AuthTestClient(self.app) as client:
+                response = client.get(f"/cases/{case.id}/download")
+
+        assert response.status_code == 200
+        # RFC 5987/6266: the UTF-8 name rides in filename*, and a latin-1 safe
+        # fallback stays in filename for old clients.
+        assert response.headers["content-disposition"] == (
+            'attachment; filename="case_multibyte.zip"; '
+            "filename*=UTF-8''%E3%83%86%E3%82%B9%E3%83%88%E4%BA%8B%E6%A1%88.zip"
+        )
+
+        archive = zipfile.ZipFile(io.BytesIO(response.content))
+        assert archive.namelist() == ["現場カメラ.mp4"]
+
+    def test_download_export_case_with_ascii_name(self):
+        """An ASCII case name still gets a plain, readable filename."""
+        case = ExportCase.create(
+            id="case_ascii",
+            name="Burglary 2026-08",
+            description="",
+            created_at=10,
+            updated_at=10,
+        )
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            video_path = os.path.join(tmpdir, "ascii_export.mp4")
+            with open(video_path, "wb") as handle:
+                handle.write(b"video")
+
+            Export.create(
+                id="export_ascii",
+                camera="front_door",
+                name="Front door",
+                date=100,
+                video_path=video_path,
+                thumb_path=os.path.join(tmpdir, "ascii_export.webp"),
+                in_progress=False,
+                export_case=case,
+            )
+
+            with AuthTestClient(self.app) as client:
+                response = client.get(f"/cases/{case.id}/download")
+
+        assert response.status_code == 200
+        assert (
+            response.headers["content-disposition"]
+            == 'attachment; filename="Burglary 2026-08.zip"; '
+            "filename*=UTF-8''Burglary%202026-08.zip"
+        )