diff --git a/Tests/images/hopper_rle8_greyscale.bmp b/Tests/images/hopper_rle8_greyscale.bmp
new file mode 100644
index 00000000000..ead32ff95a4
Binary files /dev/null and b/Tests/images/hopper_rle8_greyscale.bmp differ
diff --git a/Tests/test_file_bmp.py b/Tests/test_file_bmp.py
index f214fd6bda1..776b499e089 100644
--- a/Tests/test_file_bmp.py
+++ b/Tests/test_file_bmp.py
@@ -134,6 +134,9 @@ def test_rle8():
     with Image.open("Tests/images/hopper_rle8.bmp") as im:
         assert_image_similar_tofile(im.convert("RGB"), "Tests/images/hopper.bmp", 12)
 
+    with Image.open("Tests/images/hopper_rle8_greyscale.bmp") as im:
+        assert_image_equal_tofile(im, "Tests/images/bw_gradient.png")
+
     # This test image has been manually hexedited
     # to have rows with too much data
     with Image.open("Tests/images/hopper_rle8_row_overflow.bmp") as im:
diff --git a/src/PIL/BmpImagePlugin.py b/src/PIL/BmpImagePlugin.py
index 4dc2b93c392..5aacb10da8c 100644
--- a/src/PIL/BmpImagePlugin.py
+++ b/src/PIL/BmpImagePlugin.py
@@ -321,7 +321,8 @@ def decode(self, buffer):
                     # align to 16-bit word boundary
                     if self.fd.tell() % 2 != 0:
                         self.fd.seek(1, os.SEEK_CUR)
-        self.set_as_raw(bytes(data), ("P", 0, self.args[-1]))
+        rawmode = "L" if self.mode == "L" else "P"
+        self.set_as_raw(bytes(data), (rawmode, 0, self.args[-1]))
         return -1, 0