Triangular temporal alopecia (TTA) is an asymptomatic, circumscribed, non-scarring form of alopecia that affects the temporal scalp. Although TTA is most often seen between ages two and nine, the condition has rarely been described in adults. If unrecognized, adulthood TTA can be misdiagnosed, leading to unnecessary steroid treatment. This case report describes TTA in an adult woman who had no prior history of alopecia. It also reviews the existing TTA literature, describing the diagnosis and management of this condition.