Belgium reached the finals for the first time since 2002 by finishing top of their qualifying pool and are expected to perform well at the tournament, which starts in Brazil on June 12.
Marc Wilmots' men have been drawn in Group H for the finals alongside Algeria, Russia and South Korea and will be fancied to progress to the last 16.
However, Atletico Madrid shot-stopper Courtois, who is on loan at the Spanish club from Chelsea, feels Belgium need to approach the competition with humility.
"We're looking at the World Cup as a great experience and we're going to try and go as far as we possibly can," Courtois told FIFA.com.
"People in Belgium are talking about winning the competition or equalling (Belgium's best-ever finish of) fourth place from 1986, but we need to be realistic and keep our feet on the ground.
"We could win our group and get Germany or Portugal next. Even if we beat them we could get Argentina after that. Then there are the likes of Brazil and Spain.
"There are so many good teams with a level of experience we just don't have. We've got loads of players at big clubs but a World Cup is a world apart. You have to approach it with humility."
Belgium begin their World Cup campaign against Algeria on June 17.
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