This paper analyzes the degree of concentration, competition, efficiency and their relationship in the Indian banking sector over the period 1980-2011. The sample period is divided into three sub-periods: pre-reforms period (1980-89) liberalization period (reforms 1990-1998), and post-reform period (1999-2011). The analysis is carried out using bank level balance sheet data by employing structural measures (CR3, CR5, CR8 and HHI on total assets and deposits), non-structural measures (Panzar-Rosse model on total revenue and interest revenue as the dependent variables), Data Envelopment Analysis (DEA), and Granger-causality test. Our results indicate that Indian banking sector was highly concentrated, efficient and competitive in the pre-reforms period. However, it is not the case in the reforms and post-reforms periods. There is a significant declining trend in terms of concentration, efficiency and competition. Granger-causality test reveals that when the competition is measured using total revenue as the dependent variable then efficiency Granger-causes the competition and competition does not Granger-cause the efficiency. On the other hand, when the competition is measured using interest revenue as the dependent variable then competition Granger-causes the efficiency and efficiency does not Granger-cause the competition. On the whole, Indian banking industry operates under monopolistic competition.