| 1884 U.S. National Championships | |
|---|---|
| Date | August 26–27 |
| Edition | 4th |
| Surface | Grass |
| Location | Newport, Rhode Island, U.S. |
| Venue | Newport Casino |
| Champions | |
| Singles | |
 Richard D. Sears | |
| Doubles | |
| Richard D. Sears / James Dwight | |
List of champions of the 1884 U.S. National Championships (now known as the US Open). The tournament was held from August 26 to August 27 on the outdoor grass courts at the Newport Casino in Newport, Rhode Island. It was the 4th U.S. National Championships and the second Grand Slam tournament of the year.