The excellent py.exe launcher on Windows always uses a python.exe interpreter (although another issue suggests it will use pythonw.exe when the python file has a .pyw suffix which is good).

However, if one wanted to provide a .bat file like this:

@echo off
pushd %~dp0
py -3 MyGuiApp.pyw %*
popd

python.exe would be used rather than pythonw.exe.

My suggestion is to add a -w and/or --win(dows) flag which forces the use of pythonw.exe.

pyw.exe is installed alongside py.exe, is it insufficient?

py.exe is a console application. There's no point in using it to run pythonw.exe. Use pyw.exe, as Zachary suggests. Or better yet, just run `MyGuiApp.pyw %*`. Unless you've reconfigured the .pyw file association, it should run via pyw.exe.

Sorry, I didn't even know that pyw.exe existed. Naturally pyw -h produces no output, but maybe py -h could mention it?

> Naturally pyw -h produces no output

It needs help: `pyw -h 2>&1 | more`. This sets the StandardOutput and StandardError as the write end of a pipe. more.com reads from the pipe and pages the help text to the console. 

Maybe this needs a new issue to have `pyw -h` pop up a message box with the help text.