Personality disorders are complex and highly challenging to treatment providers; yet, for clients with these problems, there exist very few treatment options that have been supported by research. Given the lack of empirically-supported therapies for personality disorders, it can be difficult to make treatment decisions for this population. The purpose of this paper is to present our view that basic behavioral principles can be integrated into the assessment and treatment of personality disorders to maximize success with such challenging behavioral patterns. Following a review of well-established behavioral assessment and treatment options, we offer additional suggestions upon which to base treatment: (a) the identification of relevant response classes and (b) the use of functional analysis in personality disorder treatment. We conclude with application of the proposed strategies to the examples of borderline and avoidant personality disorders. (Contains 1 figure.)