ObjectiveThe aim of this study was to explore the effectiveness of schema therapy (ST) in older adults with borderline personality disorder (BPD).MethodsMultiple baseline case series design with five BPD patients, with a mean age of 66. After a baseline phase with random length, patients received weekly ST sessions for a year, followed by follow‐up sessions during 6 months. Participants rated the credibility of negative core beliefs weekly; various secondary outcome measures were assessed every 6 months (severity of BPD, early maladaptive schemas, schema modes, personality functioning, maladaptive personality traits, psychological distress and quality of life), and BPD diagnosis was assessed before baseline and after follow‐up. Data were analysed with mixed regression analyses and paired t‐tests.ResultsResults revealed that ST led to a significant decrease in credibility of negative core beliefs, with high effect sizes. All participants remitted from their BPD diagnosis.ConclusionThis is the first study exploring the effectiveness of ST for BPD in older adults, and it suggests that ST can be a powerful intervention for this group of patients.