Background Bereavement following disasters is a devastating experience for family members. The aim of this study was to examine the long‐term mental health effects of losing a loved one in a natural disaster. Methods Ninety‐four Norwegians aged 18–80 years who lost close family members in the 2004 Southeast Asian tsunami were evaluated 2 and 6 years after the disaster. The participants were either staying in an affected area at the time of the disaster (i.e., directly exposed) or not (i.e., not directly exposed). The prevalence of psychiatric disorders was assessed by the MINI International Neuropsychiatric Interview (M.I.N.I). Prolonged grief disorder (PGD) was self‐reported using the Inventory of Complicated Grief (ICG), and functional impairment was self‐reported using the Work and Social Adjustment Scale (WSAS). Results We did not identify a significant decrease in the prevalence of PGD, posttraumatic stress disorder (PTSD), or major depressive disorder (MDD) from 2 to 6 years. Approximately, one‐third of the bereaved (36%) had a psychiatric disorder 6 years after the tsunami. The most common disorder was PGD (12%) followed by general anxiety disorder (GAD, 11%), agoraphobia (11%), and MDD (10%). The prevalence of PTSD and MDD was higher among family members who were directly exposed to the disaster compared to those who were not (21 vs. 0%, and 25 vs. 3%). PGD was associated with functional impairment independent of other disorders. Conclusions Loss of a close family member in a natural disaster can have a substantial adverse long‐term effect on mental health and everyday functioning.