Objective: To ascertain the foundations for a schema-focused therapy model for the treatment of borderline personality disorder. Methods: The sample consisted of 102 borderline personality disorder outpatients. Dimensional psychopathology was assessed using the Scale for Suicidal Ideation, the Aggression Questionnaire, and the Symptom CheckList Revised. Categorical psychopathology was measured using the structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders, Patient Edition. Stepwise linear/logistic multiple regression analyses were used to determine the predictive role of the schema domains tested by the Young Schema Questionnaire on both types of psychopathology. Receiver operating characteristic curves were calculated for those binary outcomes. Results: Regarding dimensional psychopathology, disconnection/rejection predicted greater suicidal ideation (β =.39, p =.002), physical/overt aggressiveness (β =.27, p =.05), and psychotic-like symptoms, such as paranoid ideation (β =.35, p =.003). Other-directedness predicted greater anger/inner aggressiveness (β =.22, p =.05) and internalizing symptoms, such as phobic anxiety (β =.39, p =.001). Regarding categorical psychopathology, disconnection/rejection significantly predicted the presence of lifetime comorbidities with eating disorders (adjusted odds ratio [AOR] = 1.12, 95% CI = 0.99–1.24) and posttraumatic stress disorder (AOR = 1.2, 95% CI = 1.04–1.3), resulting in a good balance of sensitivity/specificity, respectively (.97/.96 and.88/.89). Other-directedness significantly predicted the absence of lifetime comorbidity with substance-use disorders (AOR =.74, 95% CI = 0.57–0.95). These relationships remained significant after controlling for confounders (e.g., comorbidity with other personality disorders, clinical global severity). Conclusions: Two schema domains, disconnection/rejection and other-directedness, were directly associated with dimensional and categorical psychopathology among borderline personality disorder patients. These findings provide further information about the foundations and target interventions when implementing schema-focused therapy on this population.