ionGroup does not exactly map the optparse.OptionGroup interface. There is no parser object to supply, but it is possible to set default values and option_lists. Also the default values and values are not shared with the OptionParser. To pass a OptionGroup into a function which expects a GOptionGroup (e.g. gnome_program_init() ). OptionGroup.get_option_group() can be used. For further help, see optparse.OptionGroup. Ú