Zimmerius is a genus of Neotropical birds in the family Tyrannidae. The genus was erected by the American ornithologist Melvin Alvah Traylor Jr. in 1977 with the golden-faced tyrannulet (Zimmerius chrysops) as the type species. The name Zimmerius was chosen to honour the American ornithologist John Todd Zimmer (1889-1957) who specialised in the classification of Neotropical birds.