Villas-Boas has defended Bale after the winger was booked for diving for a second successive game in Tottenham's 3-0 win over Fulham.
"Gareth is so fast so it is very difficult (for referees) to judge situations," Villas-Boas said.
"He has suffered big, big injuries to his ankles before and sometimes he wants to protect himself a little bit. He might put his body in situations that the referee thinks that he is diving and he is suffering for it in these last two games.
"He is now very near suspension for two unfair yellow cards and I think you gain a reputation for being a diver unfairly sometimes. This player has suffered a lot in his career. It's a little bit harsh on him."