Courtois is on-loan this season with Atletico Madrid, which are keen to sign him permanently.
"Before the end of the season I will make a decision," said the Belgian.
"It 's true that, at the moment, I'm not sure what will happen next season, because it's not just me who will decide. Any decision will be made the right way. It would be nice to play in the Champions League with Atletico Madrid. ... We'll see."