- Source: 1921 VJFL season
The 1921 VJFL season was the 3rd season of the Victorian Junior Football League (VJFL), the Australian rules football competition operating as the second-tier competition to the Victorian Football League (VFL). The home-and-away season began on 7 May and ended on 17 September.
Essendon Juniors won its first premiership in its first season, defeating reigning premiers Collingwood District.
In addition to Essendon Juniors, Coburg joined the VJFL in 1921, replacing University A and West Melbourne (the junior team of Essendon). Coburg had been playing in the Melbourne District Football Association and won three premierships in that competition, the most recent in 1920.