diff --git a/setup.py b/setup.py
index 8eb0b3c6b..dcb188872 100755
--- a/setup.py
+++ b/setup.py
@@ -439,9 +439,13 @@ class pil_build_ext(build_ext):
             # alpine, at least
             _add_directory(library_dirs, "/lib")
 
-        # on Windows, look for the OpenJPEG libraries in the location that
-        # the official installer puts them
         if sys.platform == "win32":
+            if PLATFORM_MINGW:
+                _add_directory(include_dirs,
+                               "C:\\msys64\\mingw32\\include\\libimagequant")
+
+            # on Windows, look for the OpenJPEG libraries in the location that
+            # the official installer puts them
             program_files = os.environ.get('ProgramFiles', '')
             best_version = (0, 0)
             best_path = None
diff --git a/winbuild/appveyor_install_msys2_deps.sh b/winbuild/appveyor_install_msys2_deps.sh
index f8cb8c641..7c1a2907d 100644
--- a/winbuild/appveyor_install_msys2_deps.sh
+++ b/winbuild/appveyor_install_msys2_deps.sh
@@ -5,7 +5,8 @@ pacman -S --noconfirm mingw32/mingw-w64-i686-python3-pip \
 	   mingw32/mingw-w64-i686-python3-setuptools \
 	   mingw32/mingw-w64-i686-python2-pip \
 	   mingw32/mingw-w64-i686-python2-setuptools \
-	   mingw-w64-i686-libjpeg-turbo
+	   mingw-w64-i686-libjpeg-turbo \
+	   mingw-w64-i686-libimagequant
 
 C:/msys64/mingw32/bin/python3 -m pip install --upgrade pip