She continued: "The most special girl. This little face. I will miss it as it keeps changing. Five years of loving you and forever more to go. I will always be there for you storm girl."
In a special touch, Kylie further paid tribute by resharing a photo from a fanpage which compared Stormi to Kylie at her age - but fans were divided as to whether the five-year-old actually resembles her mum.
“Stormi! U look like mommy baby!" one fan commented, quoting Kylie herself.
But others weren't convinced, with one commening: "Y’all know she don’t look like her momma 😂😂."
Stormi was born on the 1st February 2018, while her younger brother Aire was welcomed on 2nd February 2022.
As is Jenner fashion, Kylie has gone all out for Stormi's special day, throwing her an iconic shindig.
Taking to her Instagram stories, the Kylie Cosmetics creator shared photos from the birthday bash, including a room full of balloons, a floral birthday cake, and matching shirts for Stormi and Aire - which read "Stormi five is live" and "Aire to the throne".
What's more, the 25-year-old also wheeled out the infamous Stormi's World inflatable rainbow slide for another year (recycling queen!).
The party seemed to be very much Stormi focused - so no doubt Kylie will throw a separate shindig for her younger child, Aire.