The 14th-seeded Haddad Maia shook off a slow start against the seventh-seeded Jabeur on Court Philippe Chatrier and will next face Iga Swiatek, who defeated Coco Gauff 6-4, 6-2 in a rematch of last year's French Open final.
After playing nearly four hours to beat Sara Sorribes Tormo in the fourth round, Haddad Maia won only one service game in the first set. But she saved the only two break points she faced in the second set -- both in the 11th game to go up 6-5 -- and won the tiebreaker.
The 27-year-old Brazilian started the deciding set with a double break and a 3-0 lead. A frustrated Jabeur flipped her racket in the air after sending an easy backhand wide on a break-point opportunity while down 4-1. Haddad Maia won the game and served out the match.
"I had to be patient and keep doing the shots because she is a pretty good player, one of the best in the world," Haddad Maia said. "So I am proud of me and my team today because it is not easy playing her. You think you have another shot to play [in a rally] but then drop shot, winner. I always believed that the match is long."
Haddad Maia, who in 2019 was provisionally suspended for failing a doping test, is the first Brazilian woman to reach the semifinals at Roland Garros in the Open era. Maria Bueno reached the last four at the 1966 French Open and made the 1968 US Open semifinals.
Haddad Maia's fourth-round win over Sorribes Tormo, 6-7 (3), 6-3, 7-5, was the longest WTA match of the year, clocking in at 3 hours, 51 minutes. She has dropped the first set in her past three matches and has played three sets in all but her first-round victory. Entering the French Open, Haddad Maia was 1-11 in Grand Slams when losing the first set.
The last Brazilian player to win a singles title at the French Open was Gustavo Kuerten, who claimed his third championship at Roland Garros in 2001.
Jabeur, who was the runner-up at Wimbledon and the US Open last year, has been trying to become the first African woman to win a singles Grand Slam title.
"I'm hoping to go and get the title really in Wimbledon," Jabeur told reporters. "I'm dreaming about it. It's something that I always wanted.
"Last year was unfortunate because I was very close. When I put something in my mind, I know I can do it, so it's definitely here. Grass season already started in my head."
The Associated Press and Reuters contributed to this report.