Lethrinus obsoletus, the orange-striped emperor, yellow-banded emperor or yellowstripe emperor, is a species of marine ray-finned fish belonging to the family Lethrinidae, the emperors or emperor breams. This species has a wide Indo-Pacific distribution.

Taxonomy Lethrinus obsoletus was first formally described as Sciaena obsoleta by the Swedish-speaking Finnish explorer, orientalist, naturalist Peter Forsskål and published in 1775 in Descriptiones animalium, edited by Carsten Niebuhr. No type locality was given, but it is assumed to be the Red Sea. Some authors place the genus Lethrinus in the monotypic subfamily Lethrininae, with all the other genera of Lethrinidae placed in the Monotaxinae. However, the 5th edition of Fishes of the World does not recognise the subfamilies traditionally accepted within the family Lethrinidae as valid. The family Lethrinidae is classified by the 5th edition of Fishes of the World as belonging to the order Spariformes.

Etymology Lethrinus obsoletus has the specific name obsoletus, which means "worn out" or "decayed". This appears to be an allusion to the faint yellow-purple stripe, which was described as "orange-yellow" in contemporaneous accounts.

Description Lethrinus obsoletus has its dorsal fin supported by 10 spines and 9 soft rays, while there are 2 spines and 8 soft rays supporting its anal fin.