Aplocheiloidei is a suborder of the order Cyprinodontiformes consisting of three families which are commonly known as killifishes.
The three families within the suborder Aplocheiloidei are:
The only known fossil member of the suborder is the Late Miocene-aged Kenyaichthys from the Lukeino Formation of Kenya, which is the only known member of the family Kenyaichthyidae <small>Altner & Reichenbacher, 2015</small>.
Some authorities have lumped the three families into a single family, Aplocheilidae, a well-established name, chosen for its stability in usage over time, and to avoid the impact of a new name at the family rank for a popular aquarium fish group. Under this proposal, the Aplocheilidae includes three subfamilies: Aplocheilinae for the species from Asia, Madagascar and the Seychelles; Cynolebiinae (called Rivulidae above) for the species from the Americas; and Nothobranchiinae for the species from the African mainland.