The red top williamsi (Pseudotropheus williamsi) is a species of cichlid endemic to Lake Malawi where it occurs in areas with rocky substrates usually at depths of less than . This species can reach a length of TL. It can also be found in the aquarium trade. The specific name honours the Anglican missionary Joseph A . Williams who died by drowning in Lake Malawi in 1895, with Bishop Chauncy Maples, and who collected the type of the cichlid among others.