Media reports said England striker Jermain Defoe was the target of monkey chants from the away supporters, although Villas-Boas said he had not heard anything.
"I think [UEFA will take action if the accusations are proven]," Villas-Boas told reporters after the 0-0 draw.
"UEFA is very active on this kind of situation and our overall objective is to kick racism out of football.
"I can't point the finger at anyone in any way shape or form tonight because I didn't hear anything. It's for the authorities to follow up in any kind of investigation."
UEFA, whose president Michel Platini attended the game, said it would decide if any action needed to be taken once it had received a match report from the officials.
Lazio have long struggled with a right-wing element among their fans.
In another possible racism case, Chelsea have notified police after their midfielder John Obi Mikel was abused on Twitter following his side's 2-2 draw with Juventus in the Champions League on Wednesday.
"We've been made aware of racist tweets targeted at Mikel which are totally unacceptable, disgusting and abhorrent," a Chelsea statement read.
"We've informed the police and support taking the strongest possible action."
Chelsea said Nigeria international Mikel had already shut down his personal Twitter account before the remarks were published and denied that he had done so because of receiving abuse over his mistake which led to Juventus's late equaliser.
