2021 Loudoun United FC season

The 2021 Loudoun United FC season was Loudoun United FC's third season of existence, their third in the second-division of American soccer, and their third in the USL Championship.

USL Championship
The USLC realigned itself to place the current 31 teams into four regional divisions, with Loudoun in the Atlantic Division. Loudoun would play its divisional rivals four times each (evenly split between home and away matches), with the remaining four games against non-division teams.

U.S. Open Cup
Due to their ownership by a higher division professional club (D.C. United), LUFC is one of 15 teams expressly forbidden from entering the Cup competition.