See main article: 2021 Las Vegas Challenger.
Ruben Gonzales and Ruan Roelofse were the defending champions[1] but chose to defend their title with different partners. Gonzales partnered Hunter Johnson but lost in the first round to Hans Hach Verdugo and Miguel Ángel Reyes-Varela. Roelofse partnered Christopher Rungkat but lost in the quarterfinals to William Blumberg and Max Schnur.
Blumberg and Schnur won the title after defeating Jason Jung and Evan King 7–5, 6–7(5–7), [10–5] in the final.