Mangelia mediofasciata is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
Originally described as a variety of Bela nebula <small>(Montagu, 1803)</small>, it is distinct by its shorter height and its more pronounced and more limited sinus. Its outer lip is more inflected. There is a white band on the periphery of the body whorl.
This marine species occurs in the Atlantic Ocean off Senegal.