PurposeOrganizational diversity training is designed to enhance employees' skills and competencies regarding diversity and its management. The question of its effectiveness, and the conditions under which it thrives, remains a matter of debate. Unlike previous studies that have predominantly focused on the perspective of training participants, this study shifts the lens to the viewpoints of diversity training providers in Germany – a country where the formal requirement for diversity management was implemented relatively recently. The primary objective is to ascertain the critical factors influencing training effectiveness from the providers' perspective.Design/methodology/approachThis research draws upon case studies based on document analysis and qualitative interviews with diversity training providers across Germany.FindingsThe investigation reveals that the effectiveness of diversity training, as perceived by providers, hinges on several key factors: the organizational environment (including the widespread recognition of diversity issues and the presence of an organizational diversity framework), the attributes of diversity trainers (notably their personal familiarity with diversity) and the setting and design of the training (such as venue, duration and a blend of instructional approaches). A notable barrier to achieving effective training outcomes is the lack of supportive conditions within client companies, exemplified by limited training budgets, which impedes the accurate assessment of training effectiveness.Originality/valueThis study marks a novel contribution to the field by explicitly focusing on the perspective of diversity training providers in Germany. It provides new insights into the importance of the organizational context surrounding diversity education within the private sector.