Although the league was still called the VFL until the start of the 1990 season, the 1991 season was the unofficial 5th AFL season as the league expanded from 12 clubs to 14 clubs in 1987. The new clubs were West Coast Eagles and Brisbane Bears.
Port Adelaide, who are a successful club in the SANFL, was to be the 14th club. But their bid was squashed by SANFL. South Australia finally got a AFL club when Adelaide Crows entered this season. With the league increased to 15 clubs, from this season 6 clubs participated in the finals series.
- Allan Jeans retired and Alan Joyce returned as Hawthorn coach after taking them to the 1988 Premiership.
- David Parkin returned as Carlton coach after coaching them during the VFL years.
- Robert Shaw is appointed the Fitzroy coach.
- Former Carlton and Fitzroy player, Robert Walls is appointed as Brisbane Bears coach.
Geelong climbed 7 places which took them into the Preliminary Final. Whilst last season's premiers, Collingwood fell 5 places to 7th and out of the finals series.
Hawthorn won the premiership which is 3 AFL premierships in 4 years. After qualifying for last season's finals series, West Coast Eagles took the next step by winning the minor premiers. Whilst Brisbane Bears won back-to-back wooden spoons.
The Coleman Medal for the leading goalscorer was awarded to Tony Lockett of St Kilda. Jim Stynes of Melbourne won the Brownlow Medal.
|3||Geelong||Qualifying Semi Final|
|Qualifying Final||Geelong||Preliminary Final||Hawthorn|
|2||Hawthorn||Geelong||West Coast Eagles|
|1||West Coast Eagles||Eliminating Semi Final||West Coast Eagles|
|West Coast Eagles|