Stern delivered the punishment after meeting with Arenas earlier in the day, and with Crittenton Tuesday. Arenas already had been suspended indefinitely by Stern on Jan. 6.
Both players admitted bringing a gun or guns into the Washington Wizards' locker room - a violation of the collective bargaining agreement - after a dispute stemming from a card game on a team flight. Stern said the players expressed remorse, but added, "nevertheless, there is no justification for their conduct."
Asked during a conference call what message the penalties sent, Stern said: "We mean what we say when we say that guns are prohibited from being in our buildings and on team business.
"You will be dealt with harshly because it's very potentially dangerous to our players, to the other players and to anyone else who might be involved."
Arenas, who is forfeiting about $147,200 per game, had already been suspended indefinitely. Crittenton will lose about $13,435 per game from his $1.48-million salary.
The Wizards have 38 games left.
Arenas pleaded guilty Jan. 15 to a felony gun charge after a confrontation with Crittenton at the Verizon Center. Arenas, who is scheduled to be sentenced March 26, is in the second season of a six-year, $111-million contract.
Wizards president Ernie Grunfeld isn't ruling out the possibility of voiding the remainder of Arenas' contract.
Grunfeld says the team is exploring all its options. Of Arenas, he said: "When something serious like this happens, people have to be responsible for their actions."