The Tottenham manager is adamant Bale will not be sold in the January transfer window, despite reported interest from the La Liga champions.
Real Madrid boss Jose Mourinho is believed to be a huge fan of the 23-year-old but Villas-Boas is desperate to keep hold of his best players as they push for a Champions League qualification spot this season.
Villas-Boas said: "It is completely impossible he will leave in January. The transfer window always gives you the opportunity to strengthen your squad. Teams will lose players to African Cup of Nations, but there is a chance to strengthen a little bit.
"Ideally you'd prefer to avoid it. It's for us, we should plan our season, stick to players we see in summer, define our season in our season plan and go on from there.
"I think ideally for managers and clubs it would be a better situation if the window didn't open or opened for less than one month. For players it is important to have that possibility to go and play more."
The Tottenham boss also revealed the Welsh winger is in contention to feature against Stoke this weekend in the Premier League.
Bale picked up a hamstring injury against Fulham earlier this month, but Villas-Boas admitted he's made good progress and could return against the Potters.
Villas-Boas also went on to speak briefly about Tottenham's plans for the transfer window.
He said: "We have a big squad and our boost will come from the return of the injured players. I think at the moment we are okay, we have a good squad with excellent players."
Tottenham learned today that they will face French club Lyon in the next round of the Europa League.