Emotion regulation deficits are implicated in many forms of psychosocial distress. The aim of the present research was to investigate whether emotion regulation was the process underlying the well‐established association between low dispositional mindfulness and greater psychosocial distress. Two studies are presented that examined whether non‐acceptance of emotion and limited access to emotion regulation strategies were the processes underlying the association between low mindfulness and depression, anxiety, stress, general psychological symptoms, interpersonal distress, and social role difficulties in a student sample (Study 1) and a clinical sample (Study 2). In Study 1, there were indirect effects of mindfulness and symptom distress, depression, anxiety, stress, and social role difficulties through non‐acceptance of emotions. There were indirect associations between mindfulness and symptom distress, interpersonal distress, social role difficulties, depression, anxiety, and stress through lack of access to emotion regulation strategies. In Study 2, there were indirect associations between mindfulness and psychological symptom distress, interpersonal distress, depression, anxiety, and stress through lack of access to emotion regulation strategies. In brief, emotion regulation difficulties are, at least in part, the process underlying the association of low dispositional mindfulness and psychosocial distress.