Background: Supervisory effectiveness in long-term care facilities has been identified a key factor in staff satisfaction and quality of care. Determining its utility in Spanish speaking countries will assist with understanding different cultural and health service contexts. Objectives: To develop and psychometrically test the Supervisory Support Scale in Spanish. The Spanish version of the Supportive Supervisory Scale could be useful for cross-cultural comparisons of supervisory support, which is a key factor to improving work relationships in long-term care facilities. Methods: Validation was carried out with 405 participants in 37 long-term care facilities. One-way analysis of variance was the test of significance performed to examine the differences among the facilities and Pearson product-moment correlations were used to assess construct validation of the scale. The mean and standard deviation were calculated for each supervisory score in each facility. Structural equation modelling was used to confirm the dimensions of the scale. Results: The item-to-item correlations were positive, ranging from 0.44 to 0.78, indicating good reliability of the scale. The coefficient alpha for the total scale was 0.96. The 15-item had mean item scores which ranged from 2.89 to 3.96 (SD = 1.01–1.26). Standardised factor loadings ranged within a narrow range: 0.75-0.86 for the ‘respecting uniqueness’ latent variable and 0.76-0.88 for the ‘being reliable’ latent variable. Construct validity was demonstrated as measure was positively associated with job satisfaction (r = 0.412, p < 0.0001) and was negatively correlated with HCAs’ stress and burden. Conclusion: The two-factor solution identified in the original scale that highlighted two key attributes of the supervisor; being reliable and respecting uniqueness, was also demonstrated in the Spanish Supervisory Support Scale as there was a moderate fit of the model. Implications for practice: The Spanish version of the Supportive Supervisory Scale could be useful for cross-cultural comparisons of supervisory support in nursing facilities which is a key factor to improving staff relationships and care in nursing facilities.