diff --git a/CHANGELOG.md b/CHANGELOG.md
index b402f4b5..59754cda 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 (unreleased)=
 ## [Unreleased](https://github.com/jeertmans/manim-slides/compare/5.1.7...HEAD)
 
+(unreleased-fixed)=
+### Fixed
+
+- Fix combining assets from multiple scenes to avoid filename collision.
+  [#429](https://github.com/jeertmans/manim-slides/pull/429)
+
 (v5.1.7)=
 ## [v5.1.7](https://github.com/jeertmans/manim-slides/compare/v5.1.6...v5.1.7)
 
diff --git a/manim_slides/config.py b/manim_slides/config.py
index 3fd4f912..93dd69df 100644
--- a/manim_slides/config.py
+++ b/manim_slides/config.py
@@ -324,15 +324,19 @@ def to_file(self, path: Path) -> None:
             f.write(self.model_dump_json(indent=2))
 
     def copy_to(
-        self, folder: Path, use_cached: bool = True, include_reversed: bool = True
+        self,
+        folder: Path,
+        use_cached: bool = True,
+        include_reversed: bool = True,
+        prefix: str = "",
     ) -> "PresentationConfig":
         """Copy the files to a given directory."""
         for slide_config in self.slides:
             file = slide_config.file
             rev_file = slide_config.rev_file
 
-            dest = folder / file.name
-            rev_dest = folder / rev_file.name
+            dest = folder / f"{prefix}{file.name}"
+            rev_dest = folder / f"{prefix}{rev_file.name}"
 
             slide_config.file = dest
             slide_config.rev_file = rev_dest
diff --git a/manim_slides/convert.py b/manim_slides/convert.py
index aba86c0e..774f7998 100644
--- a/manim_slides/convert.py
+++ b/manim_slides/convert.py
@@ -404,8 +404,28 @@ def convert_to(self, dest: Path) -> None:
 
             full_assets_dir.mkdir(parents=True, exist_ok=True)
 
-            for presentation_config in self.presentation_configs:
-                presentation_config.copy_to(full_assets_dir, include_reversed=False)
+            num_presentation_configs = len(self.presentation_configs)
+
+            if num_presentation_configs > 1:
+                # Prevent possible name collision, see:
+                # https://github.com/jeertmans/manim-slides/issues/428
+                # With ManimCE, this can happen when caching is disabled as filenames are
+                #   'uncached_000x.mp4'
+                # With ManimGL, this can easily occur since filenames are just basic integers...
+                num_digits = len(str(num_presentation_configs - 1))
+
+                def prefix(i: int) -> str:
+                    return f"s{i:0{num_digits}d}_"
+
+            else:
+
+                def prefix(i: int) -> str:
+                    return ""
+
+            for i, presentation_config in enumerate(self.presentation_configs):
+                presentation_config.copy_to(
+                    full_assets_dir, include_reversed=False, prefix=prefix(i)
+                )
 
         dest.parent.mkdir(parents=True, exist_ok=True)
 
diff --git a/tests/test_convert.py b/tests/test_convert.py
index 791dfeac..2cf4d0e4 100644
--- a/tests/test_convert.py
+++ b/tests/test_convert.py
@@ -153,6 +153,28 @@ def test_revealjs_converter(
         file_contents = Path(out_file).read_text()
         assert "manim" in file_contents.casefold()
 
+    @pytest.mark.parametrize("num_presentation_configs", (1, 2))
+    def test_revealjs_multiple_scenes_converter(
+        self,
+        tmp_path: Path,
+        presentation_config: PresentationConfig,
+        num_presentation_configs: int,
+    ) -> None:
+        out_file = tmp_path / "slides.html"
+        RevealJS(
+            presentation_configs=[
+                presentation_config for _ in range(num_presentation_configs)
+            ]
+        ).convert_to(out_file)
+        assert out_file.exists()
+        assets_dir = Path(tmp_path / "slides_assets")
+        assert assets_dir.is_dir()
+
+        got = sum(1 for _ in assets_dir.iterdir())
+        expected = num_presentation_configs * len(presentation_config.slides)
+
+        assert got == expected
+
     @pytest.mark.parametrize("frame_index", ("first", "last"))
     def test_pdf_converter(
         self, frame_index: str, tmp_path: Path, presentation_config: PresentationConfig