Background: Sharps injuries remain a major occupational and infection prevention concern in healthcare settings, yet underreporting and inconsistent use of protective equipment persist despite mandatory regulations. Evidence on institutional and behavioral factors associated with reporting and preventive practices is limited. This study examined institutional, educational and behavioral correlates of sharps injury reporting among nursing professionals in the Republic of Croatia. Methods: We conducted a national-level cross-sectional survey in May 2024 using an anonymous online questionnaire. Eligible participants were nursing professionals who experienced at least one sharps injury in the previous five years. Data included sociodemographic characteristics, sharps injury reporting behavior, as well as the use of protective equipment and safety devices. Descriptive statistics were used for sample characterization. Group differences were tested using Mann-Whitney U and chi-square tests. Associations between organizational climate and reporting behavior were assessed using point-biserial correlation. Statistical significance was set at p < 0.05 (two-tailed). Result: A total of 215 participants met inclusion criteria; 88.4% were female, with a mean age of 36.4 years and a mean of 15.4 years of professional experience. Sharps injury reporting differed significantly by healthcare level: nurses working in tertiary healthcare institutions reported injuries more frequently than those in secondary care, where partial or non-reporting was more common (p = 0.048). Moreover, the use of protective equipment differed significantly by educational level, with more regular use reported by nurses with undergraduate or graduate education compared with those with secondary-level education (p = 0.028). A strong association was observed between regular use of protective equipment and sharps injury reporting: irregular or non-use of protective equipment was markedly more common among nurses who partially reported or did not report injuries, whereas regular use predominated among those who reported injuries (p < 0.001). The most frequently cited reason for non-reporting was low perceived infection risk associated with the injury. Conclusion: Sharps injury reporting is closely linked to both institutional context and preventive behavior. Higher reporting in tertiary care settings and the strong association between protective equipment use and reporting underscore the importance of organizational and safety culture factors. Infection prevention strategies should integrate reporting systems with interventions that promote consistent use of protective equipment, most notably in secondary-level healthcare settings, to strengthen surveillance and reduce preventable occupational exposures.