diff --git a/Tests/test_file_bmp.py b/Tests/test_file_bmp.py
index 3fc50ced227..fb3775d4ae7 100644
--- a/Tests/test_file_bmp.py
+++ b/Tests/test_file_bmp.py
@@ -69,6 +69,16 @@ def test_small_palette(tmp_path: Path) -> None:
         assert reloaded.getpalette() == colors
 
 
+def test_empty_palette(tmp_path: Path) -> None:
+    im = Image.new("P", (8, 8))
+
+    out = tmp_path / "temp.bmp"
+    im.save(out)
+
+    with Image.open(out) as reloaded:
+        assert_image_equal(im.convert("L"), reloaded)
+
+
 def test_save_too_large(tmp_path: Path) -> None:
     outfile = tmp_path / "temp.bmp"
     with Image.new("RGB", (1, 1)) as im:
diff --git a/src/PIL/BmpImagePlugin.py b/src/PIL/BmpImagePlugin.py
index 907931b926e..c3a5dc72b50 100644
--- a/src/PIL/BmpImagePlugin.py
+++ b/src/PIL/BmpImagePlugin.py
@@ -449,7 +449,8 @@ def _save(
     elif im.mode == "L":
         palette = b"".join(o8(i) * 3 + b"\x00" for i in range(256))
     elif im.mode == "P":
-        palette = im.im.getpalette("RGB", "BGRX")
+        # Colors used should not be zero, as that is treated as the maximum
+        palette = im.im.getpalette("RGB", "BGRX") or b"\x00\x00\x00\x00"
         colors = len(palette) // 4
     else:
         palette = None