At the end when Richmond play against Saint Francais, Coach Carter's son passes to "Worm" a fellow teammate. Worm is behind the half court line while Carter's son is in front of the half court line. In basketball this would count as a half court violation and it would be a turnover to the other team. In the movie however the game plays on.
In a scene in the Locker Room after a game, Coach Carter announces that they have qualified for a tournament. Here, we see Junior Battle take off his headband, in the next shot he has it back on, followed again with it off then on again
During the scene just after the first training session with Carter, the boys go to a café and Worm is talking about the '2 for 1 offer' with Kyra's friends. Kyra starts off holding a drink in her right hand, but between shots it switches to her holding a paper bag, then back to the drink, before Kyra and Kenyon walk off together.
During the game against St. Francis, when Richmond is making their comeback, one play they get a steal and make a lay-up. During the play Timo Cruz is seen on the court in the game. The camera then switches to the bench and clearly shows Timo sitting down clapping.
One of Coach Carter's rules in the contract stated that the players must wear ties on game day. In one scene, there is a sign in the background that reads, "Boys Basketball Game Today" and Kenyan is seen talking to his girlfriend in regular street clothes, thus violating the team rule.
At the very beginning of the movie, in the Richmond vs. St. Francis preseason game, Ken Carter's wife says St. Francis is up 22. Ty Crane then dunks the ball, presumably putting St. Francis up 24. But a shot of the scoreboard shows the score at 63-32, a 31-point margin.
While the cheerleaders are cheering during the season opener, the score is 34-30 with 3:17 left in the 2nd quarter. But the next scene shows Coach Carter pumping up the team for the game that is apparently already in the 2nd quarter.
In the championship game, late in the 4th quarter the score is shown St. Francis 68-67 over Richmond. Richmond scores to take the lead presumably. However, when the buzzer beater is made by St. Francis in the closing seconds, the scoreboard shows a final score of 70-68. It should have read 70-69 as a final score.
No doubt for poetic license, a physical padlock has been put on the gym door by Kenny Carter to "lock out" his players from practice. In real life, Carter, as depicted a part-time walk-on coach, would not have the power to lock out Richmond High School's girls basketball team, wrestling team, badminton team and PE classes. The "lockout" was symbolic, not physical.
The goof items below may give away important plot points.
When the boy's cousin (the drug dealer) is shot, the boy runs to his cousin and lays his gun down on his left side. The scene shifts and as the camera backs up from the scene, we see the gun laying on his right side.