Luiz has been linked with a move to Spain as new Barcelona manager Gerardo Martino assesses ways to improve his defensive options.
But speaking to BT Sport, Mourinho played down the chances of the Brazil international defender leaving Stamford Bridge by claiming he is a very important figure in his plans for the club.
“He is a player with four years [on his] contract, he just signed a contract last year,” Mourinho said.
“We like him. He is an important player for the club and the club is not ready to sell him for any price.”
Of reports that Luiz has said he would be interested in a move to the Camp Nou, Mourinho added: “I don’t know if he said that. What I can say is that he is not going to [leave].
“The last quotes I read were Luiz saying he is not speaking about clubs when he is with the national team, which is a fantastic quote that I appreciate.
“When they are with the national team they are national team players, they are not club players. That is the last quote I have and it is an intelligent one.”