Mecistocephalus ongi is a species of centipede in the Mecistocephalidae family.

It was described in 1934 by Japanese myriapodologist Yosioki Takakuwa.

[1][2] This species is yellow without dark patches but with a darker head, with 49 pairs of legs and a body up to at least 30 mm long in adults.

[3] The species occurs in Taiwan and Micronesia.

The type locality is Tainan.