Justin Timberlake's got some serious family drama back home in Tennessee -- where his aunt is currently locked up after allegedly stealing thousands of dollars from his parents in a check forging scheme.
According to law enforcement, Jane Harless -- whose brother Paul married Justin's mother when the singer was 5 -- was arrested in Shelby County, TN on Friday after cops say they found evidence she forged more than 100 bad checks.
Officials believe ... 53-year-old Jane was writing checks out to her herself and forging her brother's signature -- stealing more than $64,000 from JT's mom and step-dad (pictured above) from 2011 to 2013.
Jane reportedly worked for her brother before 2011 but it's unclear what she did ... or why they parted ways.
FYI -- Paul is a minority owner of the Memphis Grizzlies ... and a partner in Justin's Mirimichi golf course.
We reached out to JT's people for comment -- so far, no word back.