Lil Kim Sued -- Her Diva Antics Cost My Biz $15 MILLION!

Lil Kim's been slapped with a not-so-lil lawsuit by her former biz manager ... who claims her money-grubbing, diva-like behavior cost him MILLIONS in botched endorsement deals.

Andrew Ro says his company, International Rock Star Corp, inked a licensing deal with Kim back in August 2012 and planned to roll out a slew of products, including a perfume line, clothing line, vodka drink, energy drink, Steve Madden shoe line and even a honey maker.

Problem is Ro says Kim was a menace to work with and often refused to come to project meetings unless she was being paid extra for her time -- making it difficult to get anything off the ground.

Not only that, he says when a project was finally executed -- like her perfume -- Kim refused to promote the product and then stopped taking their phone calls.

After Kim cut contact, Ro says she fired off a cease and desist letter regarding future projects too ... and then filed a lawsuit claiming IRS tricked her into a bad licensing deal.

Ro fired back with his own suit, claiming Lil Kim's to blame and her antics cost his company $15 million.