This thesis explores the relationship between self-injurious thoughts and behaviors and the traditional Section II criteria BPD in comparison to the more recent levels of personality-functioning (LPFS) found in Section III. Individuals with personality disorders have higher prevalence rates for self-injurous thoughts and behaviors. However, the literature has sparse information on the relationship between levels of personality-functioning and self-injurious thoughts and behaviors. So, this study aimed to assess if the levels of personality-functioning predict self-injurious thoughts and behaviors over and above the categorical BPD criteria B. To do this, a binary logistic regression and linear regression were run to analyze the BPD and levels of personality-functioning in how they predict self-injurious thoughts and behaviors. The results showed the BPD criteria B and certain LPFS domain scores were significant predictors of self-injurious thoughts and behaviors.