Objective: Existing literature on the aetiology of borderline personality disorder (BPD) has primarily focused on pathological childhood experiences, while little to no research has been conducted on protective factors that may serve to ameliorate these symptoms. The current study attempts to fill this gap in the literature by comparing the rates of childhood protective factors among adolescents with BPD, psychiatrically healthy adolescents and adults with BPD. Methods: One hundred and four subjects were adolescent inpatients between the ages of 13 and 17 who met Revised Diagnostic Interview for Borderlines and Diagnostic and Statistical Manual of Mental Disorders Fourth Edition criteria for BPD. Sixty were age-matched psychiatrically healthy comparison subjects. Two hundred and ninety subjects were adult inpatients between the ages of 18 and 35 who met Revised Diagnostic Interview for Borderlines and Revised Diagnostic and Statistical Manual of Mental Disorders Third Edition criteria for BPD. All three groups were interviewed by using the Revised Childhood Experiences Questionnaire, a semi-structured interview that assesses pathological and protective childhood experiences. Results: Psychiatrically healthy adolescents reported significantly higher rates of 4 out of 18 protective factors than adolescents with BPD. Adolescents with BPD reported significantly higher rates of 5 of these 18 protective factors than adults with BPD. Adults with BPD were significantly more likely to endorse having a steady after school or weekend work record than adolescents with BPD. Conclusions: Taken together, the results of this study suggest that adolescents meeting criteria for BPD report lower rates of some protective factors than psychiatrically healthy adolescents. They also suggest that they have higher rates of some protective factors than adults with BPD.