Excello is an unincorporated community in central Lemon Township, Butler County, Ohio, United States, on the south side of Middletown. It comprises roughly the area south of Oxford State Road and State Route 73, west of State Route 4, and east of the Great Miami River. The Excello Lock was a canal lock on the Miami and Erie Canal. Remnants of the lock remain as a local park. Also in Excello was former Harding-Jones Paper Company plant, which is now closed but is on the National Register of Historic Places.