The Spurs boss insists the Welshman, who scored 33 goals and picked up nine assists last campaign, will remain at White Hart Lane this year amid interest from Los Blancos.
Bale has been the subject of intense speculation this summer, with Real Madrid reported to be considering a world record bid for the 24-year-old.
Yet, even though Villas-Boas revealed Bale will not feature in the Premier League opener against Crystal Palace this weekend because of ongoing injury concerns, he did maintain that the North London outfit would not entertain offers for the Welshman.
“This is a player of great importance for Spurs and a player we are not willing to negotiate for," Villas-Boas told reporters Thursday. "We recognize the interest from other clubs, but we can’t do anything at this stage.”
Tottenham completed the signing of Etienne Capoue on Thursday morning - its fourth capture of the summer - and Villas-Boas insists the Frenchman will not be the last through the door.
"We have been very active in the transfer window – not just players coming in, but players going out. The ultimate objective is to make the team stronger than the year before," Villas-Boas said. "We couldn’t manage to get in the top four spot we wanted [last season]. Our ambition stays the same and for that to happen we have been very, very active in the transfer window. We are trimming down the squad to make it strong.
"We haven’t finished our business. We will continue to be active and hopefully have the team ready in the next few weeks."