Brilliant is an unincorporated community and census-designated place (CDP) in eastern Jefferson County, Ohio, United States, along the Ohio River. It was named after the Brilliant Glass factory that once was located in the town. Although unincorporated, Brilliant has a post office, bearing the ZIP code 43913. It is located along Ohio State Route 7. Brilliant is part of the Weirton-Steubenville, WV-OH Metropolitan Statistical Area. As of the 2010 census it had a population of 1,482.
Brilliant was formerly incorporated as a village, but it disincorporated on November 24, 1993.