The reality TV star - who has kids Mason, two, and four-month-old Penelope with partner Scott Disick - is a big fan of the British designer and loves her ''cute'' childrenswear.
Kourtney said: ''Stella is my favourite designer for Penelope. Even Mason has the pyjamas - they're so cute.''
Kourtney's sister Kim is also a big fan of Stella for her own wardrobe.
She said: ''I love British designers. I'm a big fan of Stella McCartney and Sarah Burton.''
Meanwhile, Khloe Kardashian refers the style of Rihanna and Victoria Beckham, but would never try to copy someone else's look.
She said: ''I like to take inspiration, not dress head-to-toe like someone else. I'd look crazy if I was walking around looking like Rihanna, because I'm not a rockstar.''
Kourtney, Kim, and Khloe recently launched their Kardashian Kollection fashion range, after teaming up with British high street store Dorothy Perkins.