The oak titmouse (Baeolophus inornatus) is a passerine bird in the tit family Paridae. The American Ornithologists' Union split the plain titmouse into the oak titmouse and the juniper titmouse in 1996, due to distinct differences in song, preferred habitat, and genetic makeup.
The oak titmouse and juniper titmouse appear almost identical, but differ in voice as well as range. The oak titmouse gives a repeated series of three to seven syllables, each comprising one low and one high note, while the juniper titmouse song consists of a series of rapid syllables on the same note. Ranges overlap only in a small area in California. The oak titmouse has a browner back than the juniper titmouse. The tufted titmouse, which does not overlap in range, has a whiter belly, rusty flanks, and black on the forehead.