Borderline personality disorder (BPD) is a severe and generally chronic disorder that presents patients and their family members with multiple challenges. Little is currently known about how much family members of patients with BPD know about this disorder. Thirty-two family members of BPD patients were assessed for their level of knowledge about BPD. Knowledge level was then correlated with family members' burden, depression, distress, and expressed emotion. Contrary to expectation, greater knowledge about BPD was associated with higher levels of family members' burden, distress, depression, and greater hostility toward patients. These findings raise concerns about (a) the value of information family members receive about BPD and (b) the importance of the source and accuracy of the information they receive. Further research is warranted and may provide additional information to this understudied area.