Pain, a widespread challenge affecting daily life, is closely linked with psychological and social factors. While pain clearly influences daily function in those affected, the complete extent of its impact is not fully understood. Given the close connection between pain and psychosocial factors, a deeper exploration of these aspects is needed. In this study, we aim to examine the associations between psychosocial factors, pain intensity, and pain-related disability among patients with chronic pain. We used data on 4285 patients from the Oslo University Hospital Pain Registry, and investigated pain-related disability, pain intensity, pain catastrophizing, psychological distress, perceived injustice, insomnia, fatigue, and self-efficacy. We found significant associations between all psychosocial variables and pain-related disability, even after adjusting for demographic factors. In the multiple regression model, sleep problems and pain intensity were identified as primary contributors, alongside psychological distress, and fatigue. Combined, these factors accounted for 26.5% of the variability in pain-related disability, with insomnia and pain intensity exhibiting the strongest associations. While the direction of causation remains unclear, our findings emphasize the potential of interventions aimed at targeting psychosocial factors. Considering the strong link between psychosocial factors and pain-related disability, interventions targeting these factors-particularly insomnia-could reduce disability and enhance quality of life in those who suffer.