Eresia lansdorfi, the false erato or Lansdorf's crescent, is a butterfly of the family Nymphalidae.

Eresia lansdorfi has a wingspan of about 60 mm. The upperside of the wings is black. The forewings have a yellowish basal stripe, while the postdiscal area is light red brown, including the costal bar. The hindwings have a pale yellow transverse band. This medium-sized species imitates (Batesian mimicry) two local subspecies of Heliconius erato (hence the common name) and Heliconius melpomene. Larvae feed on Ruellia brevifolia.

This species can be found in Brazil, Northern Argentina, Paraguay, Uruguay and Peru.