Jabeur, who was beaten in last year's final, looked destined to suffer more heartbreak on Centre Court when she lost the opening set, but her delicate strokeplay and clever angles eventually subdued the relentless power of Belarusian Sabalenka.
The victory set up a final between the Tunisian sixth seed and unseeded Czech Marketa Vondrousova, the former French Open finalist who ended the hopes of Ukrainian Elina Svitolina earlier on Thursday.
Jabeur, who also finished runner-up at last year's U.S. Open, lost a tense first-set tiebreak and fell 4-2 down in the second, but roared back with two breaks to level the contest.
"I'm very proud of myself because maybe the old me would have lost the match today and went back home already, but I'm glad that I kept digging very deep and finding the strength," she said.
Jabeur, who is bidding to become the first African woman as well as first Arab to win a major, has shown real steel to come through this year, becoming the first woman to defeat three top-10 opponents at Wimbledon since Serena Williams, perhaps one of the game's toughest competitors, in 2012.
Sabalenka, who missed last year's tournament due to Wimbledon's ban on Russian and Belarusian players, was as tough an opponent as she could have faced.
The second seed possessed an envious recent Grand Slam record having won the Australian Open in January and reached the last four at Roland Garros while the world number one spot was hers had she beaten Jabeur.
ROARING BACK
The opening set was tight with both players seeing break points slip through their fingers before it moved into a tiebreak.
Jabeur claimed the box seat when she guided a stunning forehand down the line for a 4-2 lead but Sabalenka came roaring back, winning the next four points to set up two set points.
She let the first one go begging before Jabeur sent a return long to hand the opening set to the Belarusian, only the third that Jabeur had lost in the tournament so far.
By this point, Sabalenka had started grunting loudly on serve, with some of her roars lasting so long they extended beyond her opponent's return and almost joined up with her next loud exhalation.
The second set was far more of a roller-coaster, with Sabalenka earning the first break of the match in the fifth game to go 3-2 up.
With the Belarusian's serve proving rock solid up to that point, the situation was looking bleak for Jabeur, but momentum swung quickly in her favour.
A double fault from Sabalenka gave Jabeur a break point before her opponent netted a forehand for 4-4.
The pressure was right back on the Belarusian in her next service game with Jabeur setting up a set point which she gobbled up with a backhand return down the line to level the contest.
Sabalenka saved two break points in the sixth game of the third set with two huge forehand winners that flew of her racket like bullets but when Jabeur crafted a third she had no answer, sending a backhand long to put the Tunisian within sight of the finish line.
After holding serve, Jabeur earned her first two match points on the Sabalenka serve, but the world number two again gave a demonstration of her power, saving the first with an ace and the second when Jabeur's return landed long.
That only delayed the celebrations, however, as Jabeur eased to 40-0 on her serve, again spurning the first two match points before sealing a place in the final with an ace.
