The director said he failed to act in order to protect women despite knowing about several instances of alleged sexual assault, stating: "I knew enough to do more than I did."
In a new interview Tarantino, who worked with Weinstein on some of his best known films including Pulp Fiction, said he regretted not taking action with the knowledge he had.
"There was more to it than just the normal rumours, the normal gossip," he told the New York Times. "It wasn't second hand. I knew he did a couple of these things.
"I wish I had taken responsibility for what I heard. If I had done the work I should have done then, I would not have had to work with him."
He said that he was aware of the settlement between actress Rose McGowan and the film mogul, and said his then-girlfriend Mira Sorvino told him about an incident where Weinstein reportedly made unwelcome advances and touched her.
"I couldn't believe he would do that so openly," Tarantino said. "I was like: 'Really? Really?' But the thing I thought then, at the time, was that he was particularly hung up on Mira. I thought Harvey was hung up on her in this Svengali kind of way.Because he was infatuated with her, he horribly crossed the line."
The New York Times broke the original story which reported incidents spanning almost three decades of alleged sexual harassment, assault, and rape.
On 19 October the Los Angeles Police Department announced it was opening an investigation into whether Weinstein raped an Italian model - who has not been named - in 2013.
An LAPD spokesperson told the Los Angeles Times: "The Los Angeles Police Department's robbery homicide division has interviewed a potential sexual assault victim involving Harvey Wesintein which allegedly occurred in 2013. The case is under investigation."
Last week a statement from Weinstein's spokesperson Sallie Hofmeister said: "Mr Weinstein obviously can't speak to anonymous allegations, but he unequivocally denies allegations of non-consensual sex."