Gustavia fosteri, one of several plants in the genus Gustavia known by the Spanish common name membrillo, is a species of woody plant in the family Lecythidaceae.

It is found only on Barro Colorado Island in Panama.

[2] It is threatened by habitat loss.

Gustavia fosteri is distinguished from the more abundant Gustavia superba by several features, including smaller leaves; mostly terminal inflorescences; a calyx comprising four lobes whilst that of Gustavia superba is entire; petals coloured pink throughout rather than white flushed pink; white rather than orange mesocarp "flesh" in the fruit.

This Lecythidaceae article is a stub.