Amadeus
Mel auditioned to play Amadeus Mozart.
Actor who got the part: Tom Hulce

Assassins
Turned down the Robert Rath role due to prior commitments.
Actor who got the part: Sylvester Stallone

The Avengers
Turned down the role of John Steed.
Actor who got the part: Ralph Fiennes

Batman
Mel was the first choice to play Batman, but he was already committed to Lethal Weapon 2.
Actor who got the part: Michael Keaton

Batman Forever
Mel was considered for the role of Harvey Dent / Two Face.
Actor who got the part: Tommy Lee Jones

The Big Blue
Mel was one of the actors to be offered the lead role of Jacques Mayor but turned down for an unknown reason.
Actor who got the part: Jean-Marc Barr

Braveheart
Mel nearly passed on the lead role because he felt he was too old.
Actor who got the part: Mel Gibson

Dead Poets Society
Mel was reportedly up for the lead role, when Jeff Kanew was attached as director, but wanted too much money.
Actor who got the part: Robin Williams

The Departed
According to IMDB, had to turn down a role in Martin Scorsese’s crime drama due to his commitment to “Apocalypto.”

First Knight
Gibson was considered for the role of Lancelot.
Actor who got the part: Richard Gere

The Fountain
Was considered to play the leading male role in Darren Aronfksy’s romantic sci-fi movie that spans 1000 years.
Actor who got the part: Hugh Jackman

Gladiator
Mel was offered, but turned down the lead role.
Actor who got the part: Russell Crowe

The Golden Child
Turned down the lead role of Chandler.
Actor who got the part: Eddie Murphy

GoldenEye
Mel was considered to become James Bond.

JFK
Gibson turned down the part of Jim Garrison.
Actor who got the part: Kevin Costner

The Perfect Storm
Mel was considered for the lead role but he turned it down.
Actor who got the part: George Clooney

Phone Booth
Mel was set to star as Stu but backed out.
Actor who got the part: Colin Farrell

Primary Colors
Considered for the role of Jack Stanton.
Actor who got the part: John Travolta

Proof of Life
Turned down the lead role.
Actor who got the part: Russell Crowe

Robin Hood: Prince of Thieves
Turned down the role of Robin Hood because he had just done Hamlet.
Actor who got the part: Kevin Costner

Runaway Bride
One of several actors attached at some point, because the film was in development for over 10 years.

The Saint
Was considered for the role of Simon Templar.
Actor who got the part: Val Kilmer

Schindler’s List
Gibson was interested in this film, but Steven Spielberg thought a major star would be distracting.

The Terminator
Reportedly turned down for the part of the Terminator.
Actor who got the part: Arnold Schwarzenegger

The Untouchables
Was considered to play Eliot Ness.
Actor who got the part: Kevin Costner

World Trade Center
Screenwriter Andrea Berloff reportedly had Gibson in mind while writing the screenplay.
Actor who got the part: Nicolas Cage

X-Men
Considered for the role of Wolverine.
Actor who got the part: Hugh Jackman