The Blackburn's Bluet, Green Hawaiian Blue or Hawaiian Blue (Udara blackburnii) is a butterfly in the Lycaenidae family. It is endemic to Hawaii.
The wingspan is 22–29 mm.
The larvae feed on Acacia species (including Acacia koa), Pithecellobium, Samanea saman, Perottetia sandwicensis, Dodonaea viscosa and Pipturus albidus.