Performance appraisal systems constitute a fundamental component of human resource management in public sector organisations worldwide, serving as the primary mechanism for evaluating employee performance, determining career progression, and identifying developmental needs. In the Nigerian civil service context, however, concerns persist regarding the effectiveness of these systems in actually enhancing employee productivity and service delivery. This study examines the relationship between performance appraisal systems and employee productivity in the Cross River State Civil Service, focusing on selected ministries in Calabar, the state capital. The research adopts a mixed-methods approach, combining quantitative survey data from 387 civil servants across five ministries with qualitative interviews of human resource directors, permanent secretaries, and union representatives. The findings reveal significant gaps between the formal design of the appraisal system and its practical implementation, including inadequate rater training, subjective assessment practices, delayed feedback mechanisms, and weak linkage between appraisal outcomes and tangible rewards or consequences. The study further identifies rater bias, inadequate resources, political interference, and low employee trust as key factors undermining the motivational potential of appraisals. Statistical analysis demonstrates a moderate but significant positive correlation between perceived appraisal fairness and self-reported productivity, suggesting that improvements in appraisal system integrity could enhance employee performance. The research contributes to the literature on public sector human resource management in Nigeria by providing empirical evidence on appraisal system effectiveness in a state-level civil service context. Recommendations include strengthening rater training programmes, implementing technology-enabled appraisal platforms, establishing clear performance-reward linkages, and fostering a culture of constructive feedback and continuous performance dialogue.