Former famous person Sophie Monk is out for payback -- after a nasty car accident put her in a wheelchair back in 2010 -- because now ... she's suing the driver who's allegedly responsible.
Sophie filed the lawsuit in L.A. County Superior Court -- claiming driver Delvinder Sing Bains caused her "severe injuries" when his Ford Explorer collided with the Prius she was riding in.
Sophie was spotted being rolled around in a wheelchair just days afterwards, her foot wrapped in bandages. (She is now walking again.)
Sophie doesn't specify the extent of her injuries in the lawsuit -- but says the accident put her out of work for a while ... and racked up some serious medical bills.
Sophie is suing for unspecified damages -- totaling at least $25,000.