The 21-year-old Argentine attacker has struggled at Spurs so far this season, having joined them from Roma in the summer.
"We need to be a little bit patient with him, not speaking the language, it's very difficult," Sky Sports News quotes Villas-Boas as saying.
"Not only that but coming from a completely different social background. Imagine moving from Roma to Tottenham, it's a difficult step for him.
"So we need to give him the chance to break into the team and I think eventually, when a game goes fully his way for 90 minutes, we can have him to the level he can achieve."
Villas-Boas also defended paying £30m to Roma to sign Lamela.
"We've been very careful with him and given him our full support," he said. "It's a heavy price tag, a price tag that was deserved for what he did at Roma, but I think he still needs time.
"It took him about six months to settle in Roma. Also position-wise, he started out on the left there, then had a wonderful season on the right.
"At the moment on the right is not going well for him so he shifted back to the left and I think that will come good."
Lamela moved to Roma from River Plate in 2011.