Who could forget Kris' Great Gatsby-themed birthday party? Here, Kylie and Khloe embrace each other in their glitzy and glamorous outfits!
More baby pics courtesy of Kendall! "You're still tiny to me," she wrote. Aw!
Throughout 2017 and part of 2018, Kylie and Khloe were both pregnant for the first time, making the experience all the more special.
Flashback to a different birthday of Kylie's: her 21st!
The pair of pregnant sisters show off their baby bumps with a mirror selfie.
Yes, this pair of sisters manages to make a casual hangout look chic AF!
Talk about pregnancy glow!
"Love you, mean it," Kendall captioned this candid photo in 2018, which she reshared in honor of Kylie's birthday.
Like mom Kris did, Khloe made sure to share her favorite photos of Kylie and Stormi.
Another flashback from 2018!
Now that's a throwback! Look how young all of the Kardashian-Jenner kids look.
Looking stunning, ladies!
Glam, but make it badass.
There's no forgetting this fur moment! All five sisters dressed to the nines at Kanye West's Yeezy Season 3 show in 2016.
Kendall also added this sweet snapshot of her and Kylie hanging out on the beach to her Instagram Story.
Try to ignore the crossed out "Koko" in Kourtney Kardashian's celebratory Instagram post!
In addition to this stylish photo of Kourt and Kylie, the mom of three also reshared one of the hilarious videos she used to make all the time with her sister and family friend Harry Hudson!
Like her mom and sisters, Kim Kardashian took to Instagram to wish Kylie a happy birthday. This pic of a doe-eyed Kylie donning a giant bow was among the many photos the KKW Beauty owner posted!
"My baby @kyliejenner Happy Birthday!!!" Kim captioned her Instagram post. "I can't believe you are 23 years old!!!! The funniest and most loyal person on the planet."
Kim's post continued, "Looking for pictures and finding so many funny memories makes me so happy! I love you beyond what you could image!"
Kim did some serious digging to find these.
Those poses!
What's an '00s photo without at least one person throwing up a peace sign?
Yep, another photoshoot via Kim!