Purpose: The purpose of this paper is to develop and psychometrically validate the Perceived Supervisor Leadership Style Questionnaire (PSLSQ), designed to measure employees' perceptions of their direct supervisor's leadership behaviors. Design/methodology/approach: The study applied a multi-stage psychometric validation procedure grounded in leadership and job characteristics theories. After item development, expert review, and assessment of content validity using Lawshe's method, pilot testing was conducted. Next, the internal structure of the questionnaire was examined using exploratory factor analysis, followed by confirmatory factor analysis to verify the proposed model. Model fit was evaluated using standard fit indices. Reliability was assessed with Cronbach's alpha and test-retest analysis, and theoretical validity was examined via correlations with job characteristics, supervisor support, job satisfaction, and Big Five traits. Findings: The validation results confirm that the PSLSQ can be successfully used to measure four dimensions of perceived supervisor leadership: friendliness, autonomy, feedback, and justice. The scale showed high reliability and strong test-retest stability. Convergent validity was supported by correlations with supervisor support, job satisfaction, and job characteristics, discriminant validity was largely confirmed. Research limitations/implications: The study relies exclusively on self-report measures, which may introduce common method bias. Future research should explore longitudinal effects of perceived leadership style on employee outcomes. Practical implications: The PSLSQ provides organizations with a reliable diagnostic tool for assessing employees' perceptions of supervisory behaviors. It may be used in leadership development programs, organizational climate assessments, and performance management systems. The questionnaire allows organizations to identify strengths and weaknesses in managerial behaviors and implement targeted interventions to enhance feedback quality, fairness practices, relational leadership, and autonomy support. Social implications: By promoting relational and fairness-based leadership, the tool supports more ethical and employee-centered management. Strengthening friendliness, autonomy, feedback, and justice may enhance well-being, psychological safety, trust, and overall quality of working life. Originality/value: The paper presents an original Polish measure of perceived supervisor leadership from the employee's perspective. Unlike self-report leadership tools, it focuses on employees' subjective perceptions. The study offers comprehensive psychometric validation and integrates relational and structural aspects of leadership into a unified four-factor model. (original abstract)