Many professionals have limited knowledge of how to address health literacy; they need a wider range of health literacy competencies to enhance empowerment and person-centred prevention. We evaluated whether: (1) a comprehensive health literacy training increased self-rated competencies of health professionals to address health literacy related problems and support the development of people’s autonomy and self-management abilities after training and 6–12 weeks later, (2) professionals were satisfied with the training, (3) outcomes differed for the three participating European countries. Health professionals (N = 106) participated in a multicentre pre-post intervention study in Italy, the Netherlands and Northern Ireland. The 8-hour training-intervention involved health literacy knowledge, the practice of comprehensible communication skills, shared decision-making, and enhancing self-management. Self-rated health literacy competencies and training satisfaction were assessed at baseline, immediately after training and 6-12 weeks later, and analysed by multi-level analysis. Professionals’ self-rated health literacy competencies significantly improved following training in all three countries; this increase persisted at 6-12 weeks follow-up. The strongest increase regarded professional’s skills to enhance shared-decision making and enabling self-management after training and follow-up respectively. Professionals perceived the training as relevant for practice. Competency increases seemed to be consistent across countries. In three countries, professionals’ self-rated health literacy competencies increased following this comprehensive training. These promising findings should be confirmed in a further full effect study. Implementation of this training in European education and health care may improve person-centred communication by professionals and might help to tackle health literacy related problems and to strengthen people’s abilities in achieving better health outcomes.