Speaking about the news in the same ET interview, her sisters Kim and Khloé say they think she will comes back.
"We definitely love Kourtney and we will miss Kourtney and whatever she decides to do, but people come, people go all the time in this family," Khloé, 35, said.
"We feel like it’s a revolving door, so Kourtney might leave this week, she’ll be back. They all come back."
They joked that they could do a spinoff, like Kourtney & Khloé Take Miami, Kourtney & Kim Take New York, and Kourtney & Khloé Take the Hamptons.
"Just Kim and Khloe take ..." Kim, 39, said, with Khloé adding: "Take Calabasas! It’s just Kim and I now."
Kourtney isn’t the first Kardashian family member to temporarily step away from the show. Rob quit in 2016, telling PEOPLE:, "I gained a bunch of weight and was super uncomfortable in my skin. The whole weight thing really affected me."
The E! reality show has been on the air since 2007 and has become one of the longest-running reality shows on television.