"Kylie and I laugh so hard at this all the time, because people always want to pit us against each other, thinking we have similar careers," Kardashian, 35, wrote on her website and app on Friday.
"I think it's amazing -- there's no one else I would want to be in the same business with than my sister. She teaches me so much, and I teach her so much," continued Kardashian.
"And we're both so close that it's just funny... Sometimes I hear a rumor and I'm like, 'Wait, is that true?! What's really going on? I need to call my sister.' But with this one, that has never been the case. We just are so supportive of each other, and that's really what it is."
Kardashian has 65.7 million followers on Instagram compared to Jenner's 56.5 million followers. Kardashian, however, has had almost 20 years on Jenner to gain such fans.
Jenner, 18, voiced a similar sentiment on her own website and app in a video entitled "Sister Love" a few months ago.
"People always put me and Kim in a competition, or [they say] I'm trying to be Kim, or I'm trying to steal Kim's throne. I think people forget that me and Kim are sisters. We're not in a competition. We're completely different people," Jenner explained.
"Kim inspires me. She's one of my biggest inspirations. That's not a secret! I look up to my sister. I don't think that's like, a weird thing? We have a lot of love for each other."