The study assessed bank workers’ level of job security and examined the influence of job security level on commitment to work, and workers’ performance in selected banks in Southwestern Nigeria. The study adopted cross-sectional research design. Primary and secondary data were obtained. The banks for this study were randomly selected in line with the categorization of Nigerian banks into regional (Wema Bank), national (Stanbic-IBTC Bank) and international (First Bank. The population consisted of those workers who have been working with the banks for the last three years. These comprised both permanent and contract staff in order to ensure equal representation. Quantitative and Qualitative instruments were adopted in the collection of data. Quantitative data were analyzed using descriptive and inferential statistics while qualitative data were analyzed through content analysis. The study concluded that declining job security level is inevitable in the banking industry because of reforms in the Nigeria banking sector. However, this did not lower workers’ commitment to their work and their performance.