Dan Schneider is taking producers of 'Quiet on Set' to court -- claiming they defamed him by falsely portraying him as a child sexual abuser at Nickelodeon, and ruining his reputation.

The famed TV producer just filed a defamation lawsuit, obtained by TMZ, slamming the docuseries and its creators -- including Warner Bros. Discovery, Maxine Productions, Sony Pictures Television and others -- for falsely implying he sexually abused the child actors who worked on his shows back in the day.

Dan's lawyers don't mince words ... blasting "Quiet On Set: The Dark Side Of Kids TV" as a "hit job." As you know, Dan created "The Amanda Show," "Drake & Josh," "Zoey 101," "iCarly" and "Victorious" during his tenure at Nickelodeon ... and in 'QOS,' he was the main focus.

Dan's lawsuit alleges the docuseries used manipulative editing techniques to create a false impression of Schneider. The suit claims the defendants tried to lump Schneider into the same bucket as 2 other convicted child sex offenders who worked on some of the Nickelodeon shows. He says the defendants did it all for "clickbait, ratings, and views -- or simply put, money."

As his lawyers put it, "Schneider had no knowledge of their abuse, was not complicit in the abuse, condemned the abuse once it was discovered and, critically, was not a child sexual abuser himself."

Dan goes on to claim 'QOS' used misleading statements and editing techniques in the trailer and several episodes to falsely create the impression he was a pedophile. For instance, the lawyer points to the trailer, where his rise and success at Nickelodeon was tied to -- what the series described as -- "one of the darkest chapters."

The trailer then cut to a "True Crime Event" graphic ... falsely implying the producer had committed a crime against children. The suit claims producers deliberately ignored people who would undercut their narrative.

Schneider does, however, concede in the lawsuit he was blind to some of his bad behavior toward colleagues, subordinates and cast members ... but insists such behavior was not in any way connected to child sex abuse.

He tells TMZ ... "Recently the docuseries Quiet on Set highlighted mistakes I made and poor judgment I exhibited during my time at Nickelodeon, most of which happened decades ago during my early career as a producer, working on shows for Tollin/Robbins Productions. There is no doubt that I was sometimes a bad leader. I am sincerely apologetic and regretful for that behavior, and I will continue to take accountability for it."

Still, he says he had no choice but to take legal action ... stating the docuseries is an attempt to mislead viewers for ratings.

He adds ... "They went beyond reporting the truth and falsely implied that I was involved in or facilitated horrific crimes for which actual child predators have been prosecuted and convicted. I have no objection to anyone highlighting my failures as a boss, but it is wrong to mislead millions of people to the false conclusion that I was in any way involved in heinous acts like those committed by child predators."