The article examines how and why the McDonaldization of banking system in Nigeria engenders job insecurity. This is imperative because it provides an explicit revelation of the root causes of job insecurity in the sector that other scholars have totally omitted. No Nigerian scholar has applied the thesis in relation to job insecurity, which is the major problem in Nigeria's banking industry. The article based on the analysis of secondary data and observations, therefore, draws on McDonaldization thesis to examine the upsurge of rationalization in the sector since consolidation exercise began in 2005. The article argues that the sector's rising rationalization and ensuing efficiency, calculability, predictability, and control are necessary. However, these have inevitably engendered job insecurity and its adverse consequences. Based on the critical analyses of available evidence, the article concludes that the best option is to commence resistance of the McDonaldization processes, especially those that replace human with nonhuman technology or make customers unpaid workers.