Nick & Aaron Carter's Sister Bobbie Jean Buried in Florida Funeral

Nick and Aaron Carter's late sister, Bobbie Jean Carter, has been laid to rest ... TMZ has learned.

Sources with direct knowledge tell us Bobbie Jean was buried Saturday morning in Florida -- somewhere outside of the Tampa area, specifically. We're told it was a small, private ceremony ... with only close friends and immediate family in attendance.

Unclear if Nick himself was there, but our sources say BJ's mother, Jane, gave the eulogy.

Whereas her little brother, AC, was buried here in Southern California ... we're told Bobbie's gravesite was chosen to be closer to Jane, so that she can visit her daughter regularly. TMZ has also obtained Bobbie Jean's obituary, and it mentions her famous brothers as well as her late younger sister, Leslie, who also tragically passed away in 2012.

We broke the story ... Bobbie Jean was found unresponsive in her bathroom last month -- and while she was on probation on a drug-related charge ... cops say there were no narcotics found at the scene, and no foul play is suspected. Her cause of death is unknown.

Bobbie was only 41.