Blue Jay is a census-designated place (CDP) in Whitewater Township, Hamilton County, Ohio, United States.

Blue Jay is located along Harrison Pike, 18 miles (29 km) northwest of Cincinnati.

Harrison, Ohio is located just west of Blue Jay.

The racial makeup of the CDP was 92.7% White, 1.8% Black or African American, 0.0% Native American, 0.7% Asian, 0.1% Pacific Islander, 1.0% from some other race, and 3.8% from two or more races.

14.1% of all households were made up of individuals, and 7.7% were someone living alone who was 65 years of age or older.