The Belgium international told a national team press conference that he will return to Madrid for a third successive year while he waits to become the Blues' number one
The 21-year-old has impressed in his two seasons at Atletico, winning the Europa League and the Uefa Super Cup.
And, ahead of the World Cup next year, he has revealed he will once again join them on loan for the season to ensure he maintains regular football - something that is far from a guarentee at Chelsea.
"I've chosen to stay at Atletico," Courtois told reporters.
"I have to continue playing and at Chelsea there's [Petr] Cech who has always been a great goalkeeper.
"At Atletico I'm sure I can play and I can continue to be the first-choice keeper of the Red Devils [Belgium]. In the course of the season, we will see if I return to London."