Sean O'Brien (born August 19, 1968) is a Judge of the Trumbull County Court of Common Pleas in Ohio.

O'Brien founded the Trumbull County Community Foundation, an economic development not-for-profit.

[2] O'Brien was elected to the Ohio House of Representatives in November 2010 with 64.53% of the vote, defeating Republican Geno Capone and Independent Werner Lange.

[6] In 2016, ten-year incumbent Capri Cafaro was ineligible to run for re-election to the Ohio Senate due to term-limits.

[8] While Donald Trump won the district in 2016, O'Brien easily defeated Republican Robert Allen, 56% to 44% to take the seat in the general election.