We investigated diminutive day geckos (SVL < 40 mm) of the genus Cnemaspis (Cnemaspis kandiana Group) from mainland Sumatra and islands along its western margin (Nias, Siberut, Pagai, and Enggano). The assemblage includes several species based on morphological evidence, five of which we describe as new. The new species occur in the Sumatran provinces of Aceh, North Sumatra, and West Sumatra. Finally, we provide a new key and redescriptions for three previously recognized species: Cnemaspis dezwaani, Cnemaspis modiglianii, and Cnemaspis whittenorum, based on recently collected material, and clarify contradictory information concerning their original descriptions and their key under each species account.