'Real Housewives of OC' Lynne Curtin -- Haunted By Real Tax Lien

Former "Real Housewives of Orange County" star Lynne Curtin might not be on the show any more ... but Uncle Sam wants a piece of the green she made while she was, TMZ has learned.

According to docs ... the IRS filed a tax lien against Curtin claiming the former reality TV star needs to cough up some more tax dollars from the year 2009 ... to the tune of $32,006.24.

Lynne joined "Housewives" in 2008 (Season 4) and left in 2010 (after Season 5). Which means the money she allegedly failed to pony up in 2009 ... is partly "RHOOC" gold.

It's been a rough year for Lynne, as TMZ previously reported, she and her husband called it quits on their marriage after 22 years. He is NOT listed on the lien.

A rep for Lynne tells TMZ, she was unaware of the lien and her attorneys are looking into it.