<p>The primary aim of this study was to examine the psychometric properties of the Slovak adaptation of the Psychological Immune Competence Inventory (PICI). The instrument is designed to measure psychological immunity, representing a comprehensive system of personal competencies that promote mental health and enable efficient stress management. Additionally, it is designed to provide a personalized profile of psychological resilience. The research sample consisted of 585 individuals from the general population, of whom 261 completed a 6- to 8-month follow-up. The factor structure and invariance of the instrument were assessed by structural equation modeling (SEM) using diagonally weighted least squares (DWLS). The SEM results indicated an adequate model fit after incorporating theoretically reasonable modification indices, thereby supporting the original factor structure. The scales demonstrated good internal consistency, with Cronbach’s alpha values ranging from moderate to very high levels. Invariance measurement confirmed the psychometric equivalence of the instrument across gender, age, and education groups. Test-retest reliability was acceptable to high across all scales, as indicated by intra-class and stability correlations. Overall, the Slovak version of the PICI shows appropriate psychometric properties and appears to be invariant across demographic groups, supporting its reliability and validity for use in diverse populations.</p>