Mental health needs are common among community corrections offenders and many are enrolled in some form of supervised or mandated treatment. One category of mental health problem which may be germane to both treatment completion and recidivism among those in legally supervised treatment is the diagnosis of Personality Disorder (PD). This systematic review reports on sixteen studies comprised of full or mixed legally-supervised samples of offender in community-based treatment and examines the impact of PDs on treatment completion. These studies were difficult to compare because of the differences in program setting, definition of treatment completion, definition of PD, method of PD assessment and type of treatment, among other variables. The impact of antisocial personality disorder in treatment was a common focus, and other PDs were rarely assessed. The relevance of DSM PD categories to offender management in community corrections as well as the limitations of the current PD diagnostic categories is discussed.