Hazard and Courtois have yet to sign new contracts with the Blues amid speculation Real Madrid could make a move for the pair.
But Giroud, who hit it off with Hazard on his full debut in Monday night's 3-0 win over West Brom, says Chelsea must keep hold of them.
He said: “They are very special players. They have been here a few years now and done a great job at the club.
“They are very good on the pitch but they are good guys as well. It's very important to keep that kind of player for their leadership.
“I don't have to say too much about their qualities because they show it again in this game. Obviously we need to keep them."