We conducted a multicenter, prospective, evaluator-blinded, 2-arm parallel randomized trial to compare the effectiveness of a group psychoeducational intervention (PIP) with that of standard care in dementia caregivers. The primary outcome was the burden experience evaluated by the Zarit Burden Interview. Secondary outcomes were psychological distress evaluated with the scaled General Health Questionnaire-28 items, and quality of life evaluated with the Short-Form Health Survey 12. Effectiveness endpoint was at 4 months since inception. Statistical analyses used complete case and intention-to-treat analysis (ITT). The trial recruited 238 caregivers from 22 research sites (115 randomized to PIP, 123 randomized to standard care). No differences were found in the Zarit Burden Interview scores (complete case analysis: mean difference=-1.02, 95% confidence interval=-4.41 to 2.37; ITT analysis: MD=-0.55, 95% confidence interval=-3.64 to 2.55), the Short-Form Health Survey 12 domain scores (all P>0.05), and total General Health Questionnaire-28 items scores and some of its subscales (all P>0.05) except the anxiety and insomnia subscale for the ITT analysis (P=0.03). In summary, PIP in modality of group intervention was not better than standard care to reduce caregiver burden and overall psychological distress or to improve quality-of-life domains. EDUCA-II trial registry: ISRCTN14411440.