1978 Western Championships
| 1978 Cincinnati Open | |
|---|---|
| Date | July 10 – July 16 |
| Edition | 78th |
| Category | Grand Prix Circuit |
| Draw | 64S / 32D |
| Prize money | $125,000 |
| Surface | Hard / Outdoor |
| Location | Cincinnati, Ohio, USA |
| Venue | Coney Island |
| Champions | |
| Singles | |
 Eddie Dibbs | |
| Doubles | |
Gene Mayer /  Raúl Ramírez | |
The 1978 Cincinnati Open (also known as the 1978 ATP Championships for sponsorship reasons) was a tennis tournament played on outdoor hard courts at the Coney Island in Cincinnati, Ohio in the United States that was part of the 1978 Colgate-Palmolive Grand Prix. The tournament was held from July 10 through July 16, 1978.
Champions
Men's Singles
Eddie Dibbs defeated Raúl Ramírez 5–7, 6–3, 6–2
Men's Doubles
Gene Mayer / Raúl Ramírez defeated 
Ismail El Shafei / 
Brian Fairlie 6–3, 6–3