Macrotritopus is a poorly known genus of octopuses in the family Octopodidae. As it stands, Macrotritopus contains one valid described species, Macrotritopus defilippi. Two poorly described, unresolved taxa which are known only from planktonic hatchlings have been tentively assigned and , as well as a further three undescribed Indo-Pacific species. Macrotritopus was originally described from a single juvenile specimen which was named Macrotritopus equivocus notable for having an elongated third arm. This specimen gave the name Macrotritopus larva to this form of paralarva which was misidentified as the newly hatched juveniles of . When the eggs of M. defilippi, which were kept in captivity, hatched and the resultant larvae were observed to be of the Macrotritopus larval type then the juve