State Route 190 (SR 190, Ohio 190, OH 190) is a 8.93-mile (14.37 km) long north–south state highway in the western portion of the U.S. state of Ohio. The southern terminus of SR 190 is at an intersection with SR 66 in Delphos. Its northern terminus is at an intersection with US 224 approximately 4 miles (6.4 km) east of Ottoville.

Along its path, SR 190 passes through the northern portion of Allen County and the western portion of Putnam County. There are no segments of SR 190 that are included as a part of the National Highway System (NHS). The NHS is a network of highways that are identified as being most important for the economy, mobility and defense of the nation.

SR 190 begins in Delphos, where SR 66 and SR 697 intersects SR 190. The route starts as East 5th Street in Delphos, running eastbound toward Fort Jennings Road. SR 190 follows East 5th Street until the intersection with Fort Jennings Road, and then follows Fort Jennings Road northward toward Fort Jennings. After entering Fort Jennings, SR 190 intersects SR 189 and SR 634. SR 190 continues northward and later intersects U.S. Route 224 at its northern terminus.

The SR 190 designation was applied in 1923. It was originally routed the same as it is today.