The former Shrewsbury Town striker has scored 11 goals in 18 SPL appearances this season, scoring twice against Hearts at Parkhead on Saturday.
Lennon confirmed the Canaries had a reported £5m offer rejected for the Hoops striker on Friday – and the Celtic manager is not entertaining the prospect of selling Hooper.
“I thought Gary was brilliant, he was at his best. He got two goals, but I think his all-round game was top class,” said Lennon.
He added: “We had a chat after speaking to his representatives and we wanted to make our position clear to him and he is quite comfortable with it all.
“We have made it clear that we are not selling him, we don’t want him to go, especially at this juncture of the season.
“However, everyone has their price and what Gary’s price is will be down to the board and myself to decide. What we were offered on Thursday was nowhere near our valuation of the player.
“We don’t have a set figure, however, goal scorers are at a premium and Gary is a goal scorer so we will set the bar pretty high for him. I am hearing that they [Norwich] might come again but good luck to them on that.”