||This randomized controlled trial evaluated the efficacy of complicated grief group therapy (CGGT) in the treatment of older adults meeting clinical criteria for complicated grief, as compared to a sample of older adults receiving modified grief support grouptreatment as usual (TAU). The CGGT intervention was an adaptation of complicated grief therapy administered as group therapy. A total of 39 participants were randomly assigned to conditions. Twenty-six participants completed the 16 week intervention; CGGT n = 12, TAU n = 14. Primary outcome measures included the Prolonged Grief Disorder Scale (PG-13), the Brief Grief Questionnaire (BGQ), and the Clinical Global Impressions Scale (CGI). Participants who received CGGT demonstrated higher treatment response than participants receiving TAU. While participants in both groups showed improvement in measures of complicated grief, participants in the CGGT group realized significantly greater improvement. More importantly, when complicated grief was measured on PG-13, nearly half of CGGT participants realized clinically significant improvement. On the BGQ , all 12 of the CGGT completers had scores upon follow-up that, had they scored at that level at pretest, would have disqualified them for study enrollment. This high level of clinical significance suggests that those in the CGGT group were effectively treated for complicated grief. This study offers evidence that CGGT holds promise for treatment of complicated grief in older adults and merits further inquiry in other populations.