Our favorite Instagram style moments in honor of Kourtney Kardashian's birthday

Celebrating her 40th birthday today, mom of three, Kourtney Kardashian falls in line with some of Hollywood's A-listers who just seem to get better looking with age. With her ridiculously fit body and her thriving lifestyle brand, Poosh, it's safe to say Kourt is well...living her best life.

From vinyl trench coats in Tokyo to casually sweat-suiting around L.A., there is no doubt that the oldest sister of the Kardashian Klan is also the best dressed. If you've been following Kourtney on Instagram, then we have a feeling your camera roll is full of screenshots of some her best Insta style moments.

Whether it be her signature bra pairing with wide leg pants or her unforgettable Micahel Jackson Halloween costume, we've rounded up our favorite fashion moments from Kourtney's Instagram in the gallery below.

Want to see more of Kourtney's style? Check out her ultimate style evolution below!