Oplin is an unincorporated community in Callahan County, in the U.S. state of Texas. According to the Handbook of Texas, the community had a population of 75 in 2000. It is located within the Abilene metropolitan area.

The local Jot-um Down store served as the community's former bank.

Oplin is located on State Highway 604 and Farm to Market Road 2926, 31 mi (50 km) southwest of Baird and 28 mi (45 km) southeast of Abilene in southwestern Callahan County. It is south of the Middle Fork of Pecan Bayou.

Oplin had its own school in 1940. The high school in the community dating from 1938 is used as a local music venue. Today, the community is served by the Eula Independent School District.