It would be amazing if same thing could be done with font.
The ease of this depends on whether you want the font changed for only select windows (i.e. message window but not main menu windows, shop window but not save menu, battle windows but not title screen window) or for every single window at once and whether you need it done mid-message.
If you want it done for every window and don't need it changed in the middle of a message, you can just use the script call:
Code:Font.default_name = "fontname"
Where 'fontname' is the name of your desired font (it must be put in quotation marks). The capital F on Font matters too, as it refers to the module. Font.default_size can also be used to change its size. This will affect all fonts in the game for the point of the call onwards.
However the new font name/size won't be remembered in any save files created or loaded. One way to tackle that is to store the name of it in a game variable I.E.
Code:Font.default_name = $game_variables[1]
Where variable 0001 in the database has been set to the name of your font (either through a script call or Control Variables > Script > "fontname"). Game variables do get remembered in save files - however, you will still have to run to the script call again after loading a save game in order to set the font to it, because the Font module is reset every time the game is started.
On the other hand, if it only want it changed for select windows or mid-message you will need a more in-depth script to provide that functionality.