The ruling requires county boards of elections to make provisions for early voting for people who are arrested the weekend before the election and won't be able to vote on Election Day.
David Singleton is the executive director of the Ohio Justice and Policy Center, which argued for that move.
"This is not asking for any special rule," he said. "It is just saying the law says these folks should be able to vote."
Singleton said there's a procedure for voters who are hospitalized just before Election Day, so he said qualified voters who are jailed but are presumed innocent should be able to vote too.
The OJPC says its research shows some 400 so-called "late jailed electors" were unable to vote in 2012 because of the law.