Interstate 675 (I-675) is an auxiliary interstate highway in the suburbs of Dayton in the U.S. state of Ohio. Interstate 675 serves as an eastern bypass of Dayton. I-675 measures 26.53 miles (42.70 km) in length. As originally proposed, the route was to reconnect with I-75 north of Dayton near Northridge rather than going east towards Springfield and I-70 (this was later rejected because part of the right-of-way would have gone through Wright-Patterson Air Force Base). Construction was completed in 1987, though some have lobbied to extend the highway west of Dayton.

From the north, the highway intersects with Interstate 70 near Fairborn where it starts as a four-lane highway. The highway opens to six lanes just after the intersection with N. Fairfield Rd. in Beavercreek. The next major junction is made with U.S. Route 35 which is a full-access interchange. The highway continues with three lanes each way and ends at Interstate 75 in Miami Township.