Richard Jefferson has big beef with a former NBA ball boy ... admitting he was a jerk to the guy, but explained it's all 'cause the man used to stare at his "junk" in the locker room.
Jefferson broke it all down in a now-deleted TikTok over the weekend ... responding to a video that a former ball boy had made recently.
In the ball boy's vid, he claimed Jefferson was "always condescending" and was "the biggest jerk I met."
Jefferson revealed he did, in fact, often give the guy the cold shoulder ... but said it was for good reason.
Jefferson accused the man of staring at his groin often, as well other players' ... and then comparing their sizes.
"What he's saying is true, I never interacted with him, but let me explain why," Jefferson said in his video response. "You literally admit to looking at our junks when we were in the locker room."
Jefferson continued, "That is why I didn't interact with you. That is why I avoided you ... That's why I didn't talk to you -- because you were looking at our junks the whole time."
Jefferson concluded his video by railing against the man further.
"I just thought you wanted the attention, I'll give you the attention," Jefferson said. "That is why I never interacted with you."
Jefferson played in the NBA from 2001 to 2018 -- logging minutes with 8 separate franchises. It's unclear which team and which year Jefferson interacted with the former ball boy.