Kim, 34, and 30-year-old Khloe visited their father's home country this week, but Kourtney, 35, was noticeably absent as they paid tribute at the memorial for the 1915 Armenian genocide.
Taking to Instagram to post a picture for National Siblings Day, Kourtney explained why she wasn't there.
Alongside a snap of Kim and Khloe at the memorial, Kourtney said: "I wish I was with my sisters on #siblingsday! I didn't end up going to Armenia because it was making me too anxious with three young children.
"I do wish that I could've experienced the trip with my sisters but I do know that we will all go to Armenia together someday."
Kourt and Rob we got you a souvenir!!!!!! Land in Armenia!!! ❤️□□ > >
Posted by [Khloe Kardashian](https://www.facebook.com/KhloeKardashian) on [Friday, 10 April 2015](https://www.facebook.com/KhloeKardashian/photos/a.133636917301.104771.113962087301/10153229923012302/?type=1)
Mother-of-three Kourtney gave birth to her youngest chid, son Reign Aston, in December last year.
But Kourtney and their brother Rob, 29, weren't totally left out of the trip.
Posting a photo to Facebook, Khloe revealed she and Kim had bought some land in Armenia for their siblings.
She wrote: "Kourt and Rob we got you a souvenir!!!!!! Land in Armenia!!!"