Sharing childhood photos and words of love, both daughters acknowledged Caitlyn's transition in emotional Instagram posts.
Kendall, 19, shared a photo on Instagram of herself as a toddler being embraced by her dad. "My whole life this soul was my daddy and just because your appearance is different now doesn't mean you were any less of a father to me my entire life. Happy Father's Day to the person who raised me, and taught me everything I know, my hero," Kendall wrote.
Her younger sister Kylie, 17, also posted a childhood family photo writing, "Happy Father's Day my little light of sunshine. 'You can still call my dad, Kylie. No matter what I'm always going to be your father. That's never going to change.'"
Kylie and Kendall weren't the only ones from their famous family to send love Caitlyn's way for Father's Day. Their older half-sister Khloe Kardashian shared a photo of her late father Robert Kardashian posing with her step-father.
"Thank you Lord for blessing me with not one phenomenal father but I was lucky enough to have two," Khloe wrote.
The Jenner and Kardashian siblings have been vocal in their support for Caitlyn since she gave her much-watched coming out interview with Diane Sawyer in April.
Earlier this month, Kendall toasted Caitlyn when she debuted her new name and look in Vanity Fair. "Now that's a cover," Kendall tweeted.
Yesterday, Kylie faced a far less enjoyable situation when a man approached her too closely with his cell phone camera in Beverly Hills. After the man called her "Kendall" and asked her a crude question, Kylie cooly told him to 'get the f--- out of my face."
A fan posted the video that clearly shows the fan getting much too close to Kylie, which you can see below (warning: language is NSFW):