In Nigeria, small and medium-sized businesses play a major role in employment, innovation, and economic growth. However, low productivity, high failure rates, and weak structures remain problems for many small and medium-sized businesses in Delta State. Few studies have examined how human and behavioural elements, such organisational citizenship behaviour influence performance, despite the fact that financial and regulatory issues have gotten a lot of attention. With an emphasis on organisational commitment and perceived organisational support, this study examined the effect of organizational citizenship behaviour on small and medium-sized businesses performance. 133 small and medium-sized businesses in Delta State were given structured questionnaires to complete as part of a quantitative survey study design. The regression and analysis of variance results showed that all two factors significantly improved small and medium-sized businesses performance. In addition, it was found that the factors collectively explained a significant percentage of performance outcomes, while correlation results validated strong connections. The study concludes that supportive leadership and organizational commitment stimulate small and medium-sized businesses performance which enhances their productivity and long-term sustainability. It suggests that best approaches to increase small and medium-sized businesses competitiveness are through supportive organisational policies.

Keywords: Organizational citizenship behaviour; Perceived organizational support; Small and medium enterprises; Organizational Commitment