| Election Name: | 1942 U.S. Senate Democratic primary in Arkansas |
| Country: | Arkansas |
| Flag Year: | 1924 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1937 United States Senate special election in Arkansas |
| Previous Year: | 1937 (special) |
| Next Election: | 1948 United States Senate election in Arkansas |
| Next Year: | 1948 |
| Election Date: | August 11, 1942 |
| Image1: | File:John Little McClellan.jpg |
| Nominee1: | John L. McClellan |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 134,277 |
| Percentage1: | 61.65% |
| Nominee2: | Jack Holt |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 83,516 |
| Percentage2: | 31.35% |
| U.S. Senator | |
| Before Election: | Lloyd Spencer |
| Before Party: | Democratic Party (United States) |
| After Election: | John L. McClellan |
| After Party: | Democratic Party (United States) |
The 1942 United States Senate election in Arkansas took place on November 2, 1942. Incumbent Senator John E. Miller was appointed to a federal judgeship by Franklin Delano Roosevelt, and his appointed replacement Lloyd Spencer rejoined the Navy rather than run for election.
After a highly-competitive four-way primary, U.S. Representative John L. McClellan defeated Arkansas Attorney General Jack Holt in a run-off election.
Because the Republican Party (or any other party) did not field a candidate in the general election, McClellan's primary victory was tantamount to election.
McClellan was unopposed in the general election.