<p>Drawing on the Human Resource Diversity Management (HRDM) framework and core dimensions of diversity as a conceptual basis, the present study aimed to develop and validate a new measure of diversity management (DM) tailored to the specific context of small and medium-sized enterprises (SMEs). The research was conducted in Southern Italy with a sample of SME employers, managers, and employees (<i>N</i> = 354) to assess the statistical validity and psychometric properties of the Human Resource Diversity Management Practices (HRDMP) scale. Specifically, the scale was structured around two second-order latent factors: (1) ‘HRDM’, comprising four first-order factors (Staff Recruitment and Selection, Staff Remuneration, Staff Development, and Performance Evaluation); and (2) ‘Types of Diversity’, comprising six first-order factors (Gender, Religion, Sexual Orientation, Ethnicity, Physical/Mental Ability, and Age). The satisfactory fit indices obtained from the confirmatory factor analyses, together with the reliability and validity assessments, confirmed the multidimensional structure of a 24-item measure. Further analyses revealed positive correlations between the HRDMP scale and several psychosocial and organizational constructs, including corporate social responsibility, organizational identification, sense of community, and commitment). Additionally, differences in responses were observed based on individual and organizational characteristics, highlighting the importance of accounting for these factors in the implementation of DM practices within SMEs. Theoretical and practical implications of these findings are subsequently discussed.</p>