Angel Reese was pissed off to the max on Tuesday … and she took her frustrations out on her coach’s clipboard in the process — swiping it out of her hands in the middle of the Chicago Sky’s loss!!

The outburst happened with 29.9 seconds left in the game at George Mason University … when Reese and the Sky were tied at 77-77 with the Washington Mystics.

As the Sky challenged a loose-ball foul, players headed back to the bench … and Reese was visibly upset.

The scene with 23-year-old Reese and the coach got a mixed reaction from fans on social media — some loved her competitiveness, while others criticized her, claiming she was being a sore loser.

The incident with the coach comes just two days after another Sky loss … which sparked Reese’s expletive-laced rant about the lack of calls from WNBA referees.

“I don’t give a damn if I get fined because that s*** cheap and I’m tired of this s***,” Reese said in Sunday’s post-game interview.

“I’ve been nice and I’ve been humble, but I’m tired of this s***.”

Despite the Ls and tantrums, Reese did make history as the first player in the WNBA to have 15 or more rebounds in five consecutive games.