This paper investigated the relationship between staff development and job performance of the library staff of five selected universities in Ghana. The paper examined the effectiveness of staff training and development policies, programmes, methods, training needs analysis and the monitoring and evaluation methods of the university libraries in order to establish the effectiveness of staff development initiatives in library and information services. The study adopted survey design and mixed methods approach combining qualitative and quantitative approaches in a single study. Data was largely collected with a questionnaire, while interviews were used to collect data from head librarians and heads of departments. The observation instrument was also used to confirm some information provided by the respondents. The findings of the study established that there is a positive relationship between staff training and development and work performance of library staff in the selected university libraries in Ghana. The results also revealed that even though staff development contributes greatly to effective provision of library and information services, staff training alone did not contribute to staff effectiveness. Staff development must be complemented with other human resource management strategies such as reward, promotion, retooling, etc. The paper makes recommendations on how staff development can help improve upon library staff effectiveness.