The study examined human capital development in relationship with the productivity of librarians in the Nigerian public university libraries. It employed survey research design to investigate 923 librarians in 54 public university libraries. A self-developed questionnaire was adopted and it gave a reliability coefficient of 88% to Human Capital Development and 94% to Productivity. A response rate of 67.2% was achieved. Data were analysed using descriptive and inferential statistics. It was revealed that human capital development will boost the productivity of librarians. It concluded that effective human capital development of librarians would greatly enhanced librarians’ job performance in the university libraries. The study recommended that library management should continue in developing her professional workforce so as to satisfy various clienteles in the university community.