Olbasa (Ancient Greek: Ὄλβασα) was a town in the western part of ancient Pisidia between Adada and Zorzela. It later received a Roman colony under the name of Colonia Iulia Augusta.

Its site is located near Belenli, in Burdur Province.

 This article incorporates text from a publication now in the public domain: Smith, William, ed. (1854–1857). "Olbasa". Dictionary of Greek and Roman Geography. London: John Murray.

37°18′16″N 29°59′45″E / 37.3045498°N 29.9957318°E / 37.3045498; 29.9957318