All 10 players on the court at the time were tossed for their involvement in the ugly incident that spilled into the crowd at Madison Square Garden and spread the length of the floor.
The brawl was the NBA's scariest scene since Indiana Pacers players fought with Detroit Pistons' fans on the court and in the stands in 2004.
Anthony scored 34 points before the melee took place with 1:15 left in a 123-100 victory over the Knicks.
Denver led 119-100 when Knicks guard Mardy Collins grabbed Denver's J.R. Smith around the neck — a flagrant foul — as Smith was going in for a breakaway layup. Smith got up and jawed with Collins, and New York's Nate Robinson jumped in to yell at Smith.
"They were having their way with us," Knicks coach Isiah Thomas said. "I think J.R. Smith had just made one dunk when he reversed and spun in the air. And I think Mardy didn't want our home crowd to see that again. So he fouled him."
Anthony rushed in and pushed Robinson in the neck, triggering the roughest moment, when Robinson and Smith went flying into the stands while fighting with each other. Anthony also appeared to throw a punch at Collins, and then backed away toward the center of the court.
New York's Jared Jeffries ran from the baseline toward Anthony, but was tackled by a Denver player. The brawl stretched to the other end of the court toward the Nuggets' bench before coaches and security finally pulled Smith away and restored order.
Marcus Camby, Andre Miller, Eduardo Najera, Smith and Anthony were the Nuggets who were ejected; Channing Frye, David Lee, Collins, Robinson and Jeffries were the Knicks who were kicked out.
"Clearly this isn't how we or the NBA wants to be perceived," Thomas said. "It should have been a foul and the guy takes two free throws and maybe some words, but it shouldn't have escalated. This isn't even a rivalry."
NBA spokesman Tim Frank said the league would "review the incident in its entirety. Until then, it would not be appropriate to comment."
With each team forced to put five new players on the floor, Denver finished up the win and ended a two-game losing streak. Camby had 24 points and nine rebounds, and Miller added 12 points and 10 assists.
Robinson accused the Nuggets of trying to run up the score at the end of the game.
"If we're up 20 points, we're not going to play Stephon and Eddy," Robinson said, referring to Stephon Marbury and Eddy Curry. "It's like a slap in the face, saying we're going to embarrass you like that."