| Election Name: | 1920 South Carolina Democratic Senate primary runoff |
| Country: | South Carolina |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1914 United States Senate election in South Carolina |
| Previous Year: | 1914 |
| Next Election: | 1926 United States Senate election in South Carolina |
| Next Year: | 1926 |
| Election Date: | September 14, 1920 |
| Image1: | File:Senator Ellison DuRant Smith.jpg |
| Nominee1: | Ellison D. Smith |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 65,880 |
| Percentage1: | 60.65% |
| Nominee2: | George Warren |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 42,735 |
| Percentage2: | 39.35% |
| U.S. Senator | |
| Before Election: | Ellison D. Smith |
| Before Party: | Democratic Party (United States) |
| After Election: | Ellison D. Smith |
| After Party: | Democratic Party (United States) |
The 1920 South Carolina United States Senate election was held on November 2, 1920 to select the U.S. Senator from the state of South Carolina. Incumbent Democratic Senator Ellison D. Smith won the Democratic primary and was unopposed in the general election to win another six-year term.
Smith was the leader in the first primary election on August 31 and won the runoff election two weeks later on September 14. There was no opposition to the Democratic candidate in the general election so Smith was elected to another six-year term in the Senate.
| Democratic Primary | ||
|---|---|---|
| Candidate | Votes | % |
| Ellison D. Smith | 57,423 | 48.7 |
| George Warren | 36,317 | 30.8 |
| 15,678 | 13.3 | |
| W.C. Irby | 8,454 | 7.2 |
| Democratic Primary Runoff | |||
|---|---|---|---|
| Candidate | Votes | % | ±% |
| Ellison D. Smith | 65,880 | 60.7 | +12.0 |
| George Warren | 42,735 | 39.3 | +8.5 |
|-| | colspan=5 |Democratic hold|-