I didn't know about the $mw->optionAdd('*font' => 'sans 12'); method, ++ tybalt89.

What I have been doing is to use fontCreate() to create a font for the main window then add that font to the options hashes that I apply when creating widgets.

my $mwFont = $mainWin->fontCreate(
   q{mwFont},
   -family => q{courier},
   -size   => 10,
   );
$commonLabelOpts{ -font }       = $mwFont;
$commonButtonOpts{ -font }      = $mwFont;
$commonRadioButtonOpts{ -font } = $mwFont;
...
$controlButtonFrame->Button(
   %commonButtonOpts,
   -text    => q{Quit},
...
[download]

The optionAdd() method seems simpler so I will most likely use it for new code.

Update: Changed example to correct the senior moment of choosing a widget without fonts ... what a dummy :-/