The study was implemented across the entire Slovenian prison system, consisting of 6 prisons in 13 locations and a correctional home. The survey instrument used is based on the questionnaire developed to measure the self-legitimacy of police officers, which was later modified to suit the prison environment. In both survey periods (2016 and 2022), consent was obtained from the Director General of the Slovenian Prison Administration to implement the study. In total, 565 prison workers from the entire Slovenian prison system participated in the survey (243 in 2016 and 322 in 2022). However, only fully completed questionnaires, which amounted to 436 prison workers, were included in the sample. The characteristics of both samples reflect the overall composition of prison staff in Slovenia, particularly in terms of gender, work position, and physical place of employment. In total, 15 factors were formulated from 82 variables, simplifying the interpretation: (1) self-legitimacy, (2) relations with colleagues, (3) supervisors’ procedural justice, (4) audience legitimacy, (5) obligation toward prisoners, (6) prison workers’ subculture, (7) stress, (8) satisfaction with pay, (9) willingness to use force, (10) relations with prisoners, (11) organisational commitment, (12) professional competencies, (13) cooperation between prison services, (14) support for rehabilitation, and (15) support for harsh treatment.