Emotion dysregulation frequently co-occurs with chronic pain, which in turn leads to heightened emotional and physical suffering. This cycle of association has prompted a recommendation for psychological treatment of chronic pain to target mechanisms for emotion regulation. The current trial addressed this need by investigating a new internet-delivered treatment incorporating emotional skills training from dialectical behavioral therapy (DBT). Using a single-case experimental design that is suited to heterogeneous populations and can demonstrate efficacy with a small sample, three participants with chronic pain were recruited. Participants received four weeks of online DBT skills training (iDBT-Pain intervention) which incorporated one-on-one sessions over Zoom and a web app. Results revealed compelling evidence for the intervention on the primary outcome of emotion dysregulation and were promising for the secondary outcome of pain intensity. Improvement was also identified on pre-and post-measures of depression, coping behaviors, sleep problems, wellbeing, and harm avoidance, indicating that the intervention may positively influence other factors related to chronic pain. Overall, the trial provides preliminary efficacy for the intervention to improve chronic pain. However, we recommend further investigation of the iDBT-Pain intervention, either in single case trials, which when conducted with scientific rigor may be aggregated to derive nomothetic conclusions, or in a group-comparison trial to compare with usual modes of treatment. PERSPECTIVE: This trial advances understanding of emotion-focused treatment for chronic pain and provides evidence for a viable new technological treatment. Importantly, as an internet-delivered approach, the iDBT-Pain intervention is accessible to those with restricted mobility and remote communities where there are often limited psychological services for people with chronic pain.