Juvenile White-eyed Vireo can resemble Yellow-throated Vireo but has white throat. Bell's Vireo has broken eye ring, lacks yellow spectacles, usually shows fainter wing bars and has a dark eye as an adult. Empidonax flycatchers can have an olive back, wing bars, and white underparts with yellow flanks, but lack spectacles and have dark eyes.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.