But, now, the pair are reportedly not as close as before.
Appearing on Australia's "Today" to promote her new book "The Secrets of my Life," Jenner said she and Kardashian West are not in contact currently.
"To be honest with you, I really haven't talked to her in a long time," Jenner reportedly said. "I've kind of let everything calm down, so I kind of keep my distance. I'm out right now trying to make a difference in the world."
At the heart of the tension is some of what Jenner has written in her book, including that ex-wife Kris Jenner was aware during their 24 year marriage that the former Olympian was transgender.
Kardashian West recently talked about being estranged from Jenner on "The Ellen DeGeneres Show."
"My heart breaks for my mom because I feel like she's been through so much," Kardashian West said. "[Caitlyn's] promoting this book and she's saying all these things and, you know, I just don't think it's necessary. I just feel like it's unfair and things aren't truthful."
The reality star said she wishes Jenner success "but not at our expense."
"I'll always love her," Kardashian West said. "That was my stepdad for so many years. She taught me about character and so much growing up and I just feel like I don't respect the character that she's showing now."