Mullin is a town in Mills County in northwestern Central Texas, United States.

According to the United States Census Bureau, the town has a total area of 0.5 square miles (1.3 km2), all land.

The climate in this area is characterized by hot, humid summers and generally mild to cool winters.

26.1% of all households were made up of individuals, and 15.9% had someone living alone who was 65 years of age or older.

About 25.8% of families and 34.7% of the population were below the poverty line, including 47.9% of those under the age of eighteen and 18.9% of those 65 or over.