The Blue-crowned Motmot is 41-46cm long. Nominate M. m. momota weighs 145g. The tail is very long with a bare-shafted racket tip. The upperparts are green, shading to blue on the lower tail, and the underparts are green or rufous depending on subspecies. The head has a black crown, which surrounded by a blue and purple band. There is a black eyemask, and the nape of momta is chestnut.