| Mode: | Basketball |
| Sex: | none |
| Year: | 2020–21 |
| Prev Year: | 2019–20 |
| Next Year: | 2021–22 |
| Team: | Northwestern State Demons |
| Conference: | Southland Conference |
| Short Conf: | Southland |
| Record: | 11–18 |
| Conf Record: | 9–7 |
| Hc Year: | 22nd |
| Asst Coach1: | Jeff Moore |
| Asst Coach3: | Jacob Spielbauer |
The 2020–21 Northwestern State Demons basketball team represented Northwestern State University in the 2020–21 NCAA Division I men's basketball season. The Demons, led by 22nd-year head coach Mike McConathy, played their home games at Prather Coliseum in Natchitoches, Louisiana as members of the Southland Conference.
The Demons finished the 2019–20 season 15–15, 11–9 in Southland play to finish in a tie for fourth place. They defeated Texas A&M–Corpus Christi in the first round of the Southland tournament and were set to take on Sam Houston State in the second round until the tournament was cancelled amid the COVID-19 pandemic.
|-!colspan=12 style=| Non-conference Regular season|-!colspan=12 style=| Southland Regular season|-!colspan=12 style=| Southland tournament|-Source[1]