1920 U.S. National Championships – Women's singles
# 1920 U.S. National Championships – Women's singles

Molla Mallory defeated Marion Zinderstein 6–3, 6–1 in the final to win the women's singles tennis title at the 1920 U.S. National Championships. The event was played on outdoor grass courts and held at the Philadelphia Cricket Club in Chestnut Hill, Philadelphia from September 20 through September 25, 1920. It was Mallory's fifth U.S. National singles title.

## Draw

### Final eight

| Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Finals | Finals | Finals |
| - | - | - | - | - | - | - | - | - | - |
| Helene Pollak | 6 | 8 | | | | | | | |
| Edith Sigourney | 3 | 6 | | | | | | | |
| Edith Sigourney | 3 | 6 | | Helene Pollak | 2 | 3 | | | |
| | | | | Molla Mallory | 6 | 6 | | | |
| Molla Mallory | 6 | 2 | 6 | Molla Mallory | 6 | 6 | | | |
| Eleanor Tennant | 2 | 6 | 3 | | | | | | |
| Eleanor Tennant | 2 | 6 | 3 | | | | Molla Mallory | 6 | 6 |
| | | | | | | | Marion Zinderstein | 3 | 1 |
| Eleanor Goss | 6 | 6 | | | | | | | | Marion Zinderstein | 3 | 1 |
| Martha Niles | 4 | 2 | | | | | | | |
| Martha Niles | 4 | 2 | | Eleanor Goss | 3 | 4 | | | |
| | | | | Marion Zinderstein | 6 | 6 | | | |
| Leslie Bancroft | 4 | 2 | | Marion Zinderstein | 6 | 6 | | | |
| Marion Zinderstein | 6 | 6 | | | | | | | |
