Landon Thomas Sims (born January 3, 2001) is an American professional baseball pitcher in the Arizona Diamondbacks organization.

Sims made seven appearances as a freshman on the Mississippi State Bulldogs baseball team in 2020 and compiled a 3.46 ERA before the season was cancelled due to the COVID-19 pandemic.

[8] Sims, alongside Will Bednar, threw a combined one-hitter against the Vanderbilt Commodores in the final game of the 2021 College World Series, leading the Bulldogs to their first ever championship.

[12][13] He was named the team's Opening Day starter and pitched seven innings in which he gave up one earned run, seven hits, no walks, and 13 strikeouts in a 3-0 loss to Long Beach State.

[16] On March 14, it was announced that he had torn his ulnar collateral ligament and would undergo Tommy John surgery, forcing him to miss the remainder of the season.