Background: Citizenship fatigue has been identified as a negative consequence of performing organizational citizenship behaviors and has been studied due to its undesirable effects on employees and organizations. This article aims to present the results of adapting the citizenship fatigue scale to Portuguese language and to provide evidence of its validity.

Methods: The research methodology involved multiple stages. Initially, the Citizenship Fatigue Scale was translated into Portuguese using a robust back-translation process involving three bilingual translators to ensure semantic accuracy. Subsequently, for psychometric testing, the Citizenship Fatigue Scale and Compulsory Citizenship Behavior Scale were administered to a sample of 406 employees from different economic sectors (103 male; 303 female), aged 18 to 70 years. Reliability and validity indicators were calculated from the CFA structure, employing the maximum likelihood estimation with bootstrapping. Gender invariance was examined at three different levels: [1] configural invariance [2], factor loading invariance and [3] factor loading and intercept invariance.

Results: The internal consistency, of the whole scale, measured by Cronbach's alpha, was 0.94. The composite reliability value was also very satisfactory (CF = 0.94). The variance extracted from mean (AVE) value of 0.79 was higher than the required limit of 0.50, indicating an adequate fit of the model. The confirmatory analysis supported a single-factor model and showed good to very good fit indexes (CFI = 1.00; GFI = 0.99; RMSEA ≤ 0.01). The model was successfully replicated with a male and female sample.

Discussion: The results confirm that the Portuguese version of the Citizenship Fatigue Scale is a reliable instrument for research with Portuguese speaking samples and international research.