The annual Australian Football League Mark of the Year competition (currently also known as the Four'N Twenty AFL Mark of the Year) is a sporting award that celebrates each season's best mark. A mark is the action of a player cleanly catching a kicked ball that has travelled more than 15 metres (49 ft) without the ball hitting the ground or being touched by another player (teammate or opponent).

Originally known as the "VFL Mark of the Year" and selected by a panel of football experts on Network Seven's World of Sport program, the contest was renamed the "AFL Mark of the Year" following the competition's renaming in 1990. Since 2001 it has been run by the AFL. It is open only to players within the AFL and applies to marks taken during official AFL season matches. Several other Australian rules football leagues followed with their own "Mark of the Year" competitions.

A famous VFL footballer, Alex Jesaulenko, unofficially won the first award for a "spectacular mark" during the 1970 VFL Grand Final, a mark that has been frequently called "The Mark of the Century".

Thirty-two players have won the competition; of those, five have won multiple times and six are still active in the AFL. Peter Knights (Hawthorn) and Tony Modra (Adelaide/Fremantle) have won the most Mark of the Year awards, with three each.

The competition is run in conjunction with the Goal of the Year contest, which recognizes the best goal kicked during an AFL season. Two players have won both the "Mark of the Year" and "Goal of the Year" awards in the same season: Michael Mitchell and Peter Bosustow.