The birthday girl stunned on her special day in a black, semi-sheer curve-hugging gown that showed off her flawless figure.
Kim Kardashian-West took to her Instagram story to share some snaps from the grand occasion, and gave fans a look at her stylish sister's sultry ensemble.
From the very start of the b-day bash, it was clear Kourtney had pulled out all the stops for her special day, and the reality star entered the party with all the pomp and circumstance of a queen.
Walking hand-in-hand with her six-year-old daughter, Penelope, Kourtney's grand entrance was accompanied by two rows of roaring sparkler fountains and a saxophone player performing a beautiful cover of Stevie Wonder's "Isn't She Lovely."
As for the party's decor, Kourtney and her sisters spared no expense giving their oldest sister the best, most self-referential party of all time.
First off, the stunning cake was a creation of fantastic artistic talent, and depicted a nude woman (which looks remarkably like Kourtney herself in that series of nude poolside photos she posed for years ago) sitting on the edge of a bathtub.
There were also a slew of personalized bottles of Don Julio 1942, with Kourtney's face engraved in the glass, above the words, "Most interesting to look at."
And it wasn't just the bottles that called back to their infamous fight. The party also had personalized napkins with "Most interesting to look at" printed on the lower right corner.
The flip side of the napkins also featured another famous KUWTK quote, "Kim, there are people that are dying." That, of course, was Kourtney's less-than-sympathetic response to Kim's famous freak-out after losing her diamond earrings in the ocean.
It seems like Kourtney is enjoying one monumentally fun birthday bash, and fans will get a chance to see all the small details when it inevitably plays a role in some future episode of Keeping Up later this year.