Sapi-an or Sapian is a fourth class municipality in the province of Capiz, Philippines. It belongs to the Second Congressional District of the Province of Capiz. At the 2010 census, Sapian has a total population of 24,779 people,predominantly Catholic.

Sapian Bay which is situated in the northern part of the municipality is geographically joined with Capiz Bay. The 30 km² Sapian and Capiz shallow sea bays has extensive intertidal mudflats, sandy beaches, mangrove swamps, estuaries of several small rivers, and associated coastal lagoons and marshes.

Sapian Bay which opens up to the Sibuyan Sea is a source of livelihood for many Sapianons. Marine produce from Sapian Bay include green mussels "tahong", oyster "talaba", lobster and different species of fish,and clams. Many lands near sea water were developed into fishponds that produce milkfish (bangus), prawns and crabs.

Another source of livelihood is agriculture. Carpets of rice fields, trees and flowers can be seen as one travels through Sapian along the national road which connect Roxas City to Iloilo and Aklan. The ricefield along the national road are slowly disappearing to give way to housing developments. Sapian's main agricultural produce are rice and coconuts.