Big Boy Sued -- Radio Station Says He'll Leave The Neighborhood Over Their Dead Body!

12:45 PM PT -- Big Boy released this statement Thursday:

“I feel nothing but love and gratitude for the nearly 21 years I’ve spent with my listeners at Power 106. I am proud of everything I accomplished over the last two decades and the contributions I made to the station’s success. All I want to do right now is get back to what I love, what I am meant to do – wake up every morning and hang with my listeners. They are my family. Their love and devotion mean everything to me.”

Big Boy -- one of the biggest personalities in radio -- is apparently too popular for his own good. The communications group that ran his show for decades claims Big Boy has betrayed them by jumping to a competitor and they are hell-bent on stopping it.

Emmis is taking it real personal, saying it discovered Big Boy more than 20 years ago when he was working as a bodyguard, and turned him into one of the most dynamic personalities on the air.

Big Boy was making $1.45 million a year -- plus bonuses and a car -- but his contract was up at the end of this month. According to the suit, Big Boy got an offer from iHeartMedia of $3.5 million plus other royalties and perks, including the use of a private jet.

But Emmis says it has a right under the existing deal to match a competitor's offer and keep him, and says that's exactly what it did ... but he told the company he was leaving anyway.

The outlet that carries Big Boy's Neighborhood in L.A. -- Power 106 FM -- started Wednesday's morning drive time ... his usual shift ... by playing music without a DJ, though one eventually came on around 6 AM.

But Emmis is on the attack, asking a judge for an order prohibiting Big Boy from bailing. Emmis also wants $5 million.

We called Big Boy ... so far no answer.