Republicans will continue their control over the Ohio Legislature, having secured enough seats to give them an edge in each chamber.
The GOP had majorities in both the House and Senate going into Tuesday's election.
It was a longshot for Democrats to take control of the state Senate, where the GOP has a 23-10 advantage.
Republicans have a 59-40 edge in the House. Democrats were hoping to cling to enough seats there to keep the GOP from gaining any more power.
With races yet to be called, it wasn't immediately clear what the final breakdown would be in each chamber.
The GOP's victories on Election Day mean that Republican Gov. John Kasich should have a smoother chance at getting his budget and other legislative priorities passed next session.