The Sex with Brody star is engaged to model girlfriend Kaitlynn Carter.
The couple, who have been dating since 2014, announced their engagement Friday morning on Instagram, sharing similar smooching selfies while on a tropical vacation.
"On May 4th 2016 I got engaged to my lover and my best friend Kaitlynn Carter," Jenner, 32, gushed. "I couldn't be more in love with this woman and I can't wait to spend the rest of my life with her."
Kaitlynn, 28, showed off her new bling while rocking a white bikini.
"This trip has been memorable for many reasons," she dished, calling herself the "happiest girl in the world."
The couple's engagement comes a month after stepbrother Rob Kardashian and Blac Chyna announced their engagement.
This is the first engagement for Jenner, who has had high-profile relationships in the past with Avril Lavigne, as well as with his Hills costars Lauren Conrad and Kristin Cavallari.