Villas-Boas, who won the competition with FC Porto in 2010, thinks it is unfair that the Blues, and the rest of the Champions League drop-outs, are allowed in to the tournament.
"I think it's extremely unfair," the Tottenham boss said.
"It would be much fairer if the clubs came in to the Europa League when they are knocked out of the last 16 of the Champions League.
"You can't give a bonus to teams who have failed, and in the situation as it stands, teams fail in the Champions League and are promoted to the Europa League, which, in my opinion, is a massive bonus.
"I've not made this up today. I have said this in UEFA meetings before. It's up to them to decide but I think it's not fair."