The present study investigated the (co-)occurrence of non-suicidal self-injury (NSSI) and pathological buying (PB) and their associations with reactive/regulative temperament in a sample of female patients with eating disorders (ED) and in a sample of community adults. Our samples consisted of 254 community adults (48.8% female) and 60 female patients with ED. All participants filled out self-report questionnaires to assess NSSI, PB, and reactive/regulative temperament. Prevalence rates of NSSI and PB were respectively 14.5% and 4.8% for community women, 13.1% and 1.5% for community men, and 36.7% and 10% for female patients with ED. Only for community women, NSSI was positively related to PB. NSSI was negatively related to self-regulation in community men and women. Additionally, NSSI was negatively predicted by BAS reactivity in the clinical sample and by the interaction of BAS reactivity and self-regulation in community men. PB was predicted by low self-regulation in the three groups. Additionally, PB was positively predicted by BAS reactivity and by the interaction of BAS reactivity and self-regulation in community women. These findings indicated group differences in the (co-)occurrence of NSSI and PB and in their associations with underlying temperamental characteristics between individuals with and without ED.