The structure of the Indian banking system has substantially changed over the past decades due to the new technology in the banking system and the effective implementation of the new service systems for the people. In this study, to measure the efficiency of Public Sector Banks (PSBs) and Private Sector Banks (Pvt. SBs), Data Envelopment Analysis (DEA) is used for the period 2018–19. The DEA is a branch of Operations Research (OR). The basic approaches, CCR (Charnes, Cooper, and Rohde), and BCC (Bankers, Charnes, and Cooper) have been used for evaluating efficiency scores at different levels. In addition to these approaches, a Slack-Based Measure (SBM) of efficiency is implemented to non-zero slack, and this model deals with input excess and output shortfall of the DMUs (Decision-Making Units). The result of the super-efficiency from radial CRS (Constant Returns to Scale) is that CBI bank performed with the highest efficiency and Pvt.SB Axis bank was the top performer. The results obtained from the SBM supper-efficiency of VRS (Variable Returns to Scale) are infeasible. To overcome this non-radial SBM CRS, VRS models have been used, and the results exhibited from the two models are feasible. The CBI, SBI, Vijaya, Axis, and HDFC banks are identified as top performers in these models.