Abstract: This paper investigates the effects of market-based financial sector reforms on the competitiveness and efficiency of commercial banks, and economic growth, in Zambia. The results show that reforms adopted in Phase II (strengthening of regulatory and supervisory, payments and settlements, and financial operations frameworks) and Phase III (implementation of a comprehensive financial sector development plan) had significant positive effects on bank cost efficiency. Macroeconomic variables such as per capita GDP and inflation were insignificant. Further, using an endogenous growth model in which industrial production is a proxy for GDP growth, it was found that bank cost efficiency, financial depth, Phase II and III financial sector reforms, the degree of economic openness, and rate of inflation were significant determinants of economic growth. Phase II policies and the inflation rate have negative effects while the rest of the variables have positive effects on economic growth. Some plausible policy lessons are offered.