It is pertinent for the library staff to work in the direction of providing adequate information resources that will satisfy the library users and sustain effective library service delivery. This study examined on how the availability of library facilities can enhance knowledge sharing among librarians and improves their job performance. The study adopted a descriptive survey design and total enumeration that covers staff in the three universities in Southwest Nigeria. They are the Federal University of Agriculture, Abeokuta, University of Ibadan, Ibadan and University of Lagos, Lagos. The questionnaire was the instrument used to collect data for the study. The result indicated that the majority of the staff were highly exposed to library facilities that encourage job performance. The finding revealed that some were not willing to share their knowledge because people don’t appreciate it. The study revealed that knowledge sharing had impacted greatly on their job performance. The study revealed that a relationship exists between the three variables; availability of library facilities, knowledge sharing, and job performance. Statistical Package for Social Sciences (SPSS) was used to analysis the result using descriptive statistics with tables of frequencies and percentages, ANOVA and Correlation in analyzing the data. It was recommended that the library management should endeavor to give equal opportunity to the staff in terms of staff development and training. This will, in turn, encourage staff to embrace knowledge sharing practices.