diff --git a/folium/features.py b/folium/features.py
index 587f5e053b..1638920697 100644
--- a/folium/features.py
+++ b/folium/features.py
@@ -757,8 +757,10 @@ def process_data(self, data: Any) -> dict:
             else:  # This is a filename
                 if not self.embed:
                     self.embed_link = data
-                with open(data) as f:
-                    return json.loads(f.read())
+                # Read bytes so json can detect the encoding (UTF-8 per RFC 7946)
+                # instead of decoding with the platform's locale encoding.
+                with open(data, "rb") as f:
+                    return json.load(f)
         elif hasattr(data, "__geo_interface__"):
             self.embed = True
             if hasattr(data, "to_crs"):
diff --git a/tests/test_features.py b/tests/test_features.py
index e41e0e8337..c05d57c7f1 100644
--- a/tests/test_features.py
+++ b/tests/test_features.py
@@ -232,6 +232,24 @@ def test_geojson_tooltip():
         ), "GeoJsonTooltip GeometryCollection test failed."
 
 
+@pytest.mark.parametrize("encoding", ["utf-8", "utf-8-sig"])
+def test_geojson_from_utf8_file(tmp_path, encoding):
+    data = {
+        "type": "FeatureCollection",
+        "features": [
+            {
+                "type": "Feature",
+                "properties": {"name": "東京都", "alt": "Hämeenlinna"},
+                "geometry": {"type": "Point", "coordinates": [139.69, 35.69]},
+            }
+        ],
+    }
+    path = tmp_path / "data.geojson"
+    path.write_text(json.dumps(data, ensure_ascii=False), encoding=encoding)
+
+    assert GeoJson(str(path)).data == data
+
+
 # GeoJsonMarker type validation.
 def test_geojson_marker():
     m = folium.Map([30.4, -97.5], zoom_start=10)