Chepngetich, 26, was led across the finish line in Turkey by Ethiopian Yalemzerf Yehualaw (1hr 4:40), with Kenyan Hellen Obiri, a two-time world 5000m winner, in third position in 1hr 4:51.
This was the first time three women completed a half marathon in under 65 minutes.
Chepngetich pulled away from Yehualaw in the final stages, securing her place in history and winning the race for the third time,following 2017 and 2019.
Brigid Kosgei, the Kenyan marathon record holder, set a high early pace, ultimately finishing fifth, nearly two minutes behind the winner.
Chepngetich ran the first 10 kilometres in 30:21, maintaining her pace to the finish line amid the rain.
Kibiwott Kandie, a compatriot and world record holder, won the men's race in a course record time of 59min 35sec.
This was a long way from his world-best time of 57:32, which he set in Valencia in December.
Geoffrey Kamworor, the former world record holder, finished third, three seconds behind, with Roncer Kipkorir (59:46) rounding out an all-Kenyan podium.
Kandie, the silver medalist in the world half-marathon, had enough left in the tank to fend off Kamworor within the final kilometre.
He lowered the course record set in 2018 by Amdework Walelegn, who finished fourth on Sunday, by 15 seconds.