Gillellus semicinctus, the half-banded stargazer, is a species of sand stargazer native to the Pacific coast of the Americas from the Gulf of California to Colombia, as well as occurring in the Galapagos Islands. It can be found on sandy substrates at depths of from 5mto140mm (16feetto460feetm). It can reach a maximum length of 5.2cm (02inches) TL.