The American gray flycatcher is very similar morphologically to the American dusky flycatcher ("Empidonax oberholseri"), which has been problematic in taxonomy. When described as a species in 1889, the American gray flycatcher was named "Empidonax griseus". This name was reduced to synonymy when it was discovered that the type specimen designated for the dusky flycatcher was in fact an American gray flycatcher. The name then in use for dusky flycatcher was Wright's flycatcher ("E. wrightii"), a name proposed in 1858. Because the name "wrightii" took precedence, it was applied to the American gray flycatcher, leaving the dusky flycatcher to be given a new name, "E. oberholseri".