Dialectical behavior therapy (DBT) is currently the most researched therapy method to treat borderline personality disorder (BPD). A major component of DBT is learning and practicing specific skills to regulate emotions. Qualitative studies found that patients perceived DBT skills as helpful in dealing with emotions. However, DBT consists of more than 60 different skills, and earlier qualitative studies had a broad focus. The present study explores patients' experience with a specific skill, opposite action (OA). The skill is one of the major DBT skills assumed to play an important role in symptom improvement. OA means deliberately performing a behavior that is opposite to the emotional urge to act and is intended to weaken the original emotion. Qualitative data from semistructured interviews with 23 patients diagnosed with BPD receiving DBT were analyzed following qualitative content analysis procedures. The participants generally had a good understanding of the skill, although it was often mixed with other skills of DBT. Performing OA was perceived as exhausting. Adverse effects of OA, intense emotions and high distress were reported as barriers to OA use. However, participants named several factors that helped them overcome these barriers, including their thoughts and actions, support from others, and treatment elements. Participants described positive effects of OA such as positive emotional changes and a decrease in problem behavior and more freedom in everyday life. The findings of the study provide valuable information to optimize the delivery of OA and DBT and can help to improve treatment outcome for patients with BPD. Clinical Impact Statement Questions: What are patients' experiences with the DBT skill OA? Findings: Patients generally reported positive emotional changes, decreases in dysfunctional behavior, and more freedom in everyday life with using OA, though they also perceived acting opposite as exhausting, especially when feeling intense emotions and high distress. Meaning: OA is an important skill to facilitate improvements in emotion regulation. Based on participants' statements, clinicians can optimize the teaching of OA and help clients to overcome obstacles in the use of OA. Next Steps: Future qualitative research should take a closer look at other specific skills of DBT.