Conte's future at Stamford Bridge has been in doubt for several months and Courtois feels that the negative environment has been a major factor in Chelsea finishing a lowly fifth in the Premier League.
The Italian has just one year remaining on his current deal and the Blues have drawn up a short-list of managers to replace him including Maurizio Sarri, Luis Enrique, Massimiliano Allegri and Leonardo Jardim.
Chelsea considered getting rid of Conte, who led the club to the FA Cup on Saturday, earlier in the campaign but were reluctant to pay him compensation.
Courtois feels a decision over Conte needs to be made one way or another for Chelsea to progress and said: "I don't think it is a question for the players, it is a question for the board.
"I think we trained very well with him. Obviously this season has been tough. But I think there has to be a clear line from the club to continue or to stop.
"You can not have him one more year and then not know if he will go away the next year or not. You need some clarity so that everyone knows what way the club is going forward.
"It is what we lacked this season. There were always rumours about everyone and it is not easy then to defend the title, with all the criticism.
"You get questions before and after games and eventually it turns around the group. we felt it inside Cobham where we trained.
"There was a negative spirit sometimes and then it's hard to raise yourselves. We had some great moments, but then we'd lose lose one game and then another one.
"We came back but it was too late.
"We are very happy to end with a trophy but we are obviously not happy to not reach the Champions League."
Courtois' stay at Chelsea is also in question as the keeper's contract expires in 2019 and he continues to be linked with Real Madrid.
The 26-year-old, who is also being targeted by Paris Saint Germain, has urged the hierarchy to spend big in the transfer window in order for the club to make a better challenge for the League next term.
When asked for an update on his future, the Belgium international replied on BT Sport: "I don't know. Maybe I will speak with Chelsea after the World Cup. I love this club, I love to be here.
"But I need to see in what way this club is going forward. Obviously we want to win trophies like the FA Cup, but we want to play for the title again.
"We need some big additions. We can see how Manchester City and Manchester United are spending. If Chelsea want to be a club on top, they need to show it as well."