The first barangays of the municipaity were Sibulan, Dampalan, Labag, Princesa Lamaya and Marong – all of which were part of the Municipality of Piñan. Sibulan became its capital and seat of government.
Sergio Osmeña is composed of 39 barangays. Each barangay differs in terms of their topography, land area and development. Urban barangays are Poblacion Bajo, where the central elementary and high schools are found and Poblacion Alto, which is the center of commerce and business establishment.
