While the importance of the banking sector on various fundamental economic variables is well-documented in the literature, little is known about the relationship between the bank market structure and access to finance for opaque firms, particularly in developing economies such as South Africa. Using ordered probit and logit models, we investigate the impact of bank market structure on small, micro and medium enterprises (SMMEs)access to finance. Our results show that high bank concentration increases the obstacle to accessing finance for SMMEs in South Africa, and the relationship is non-linear. Thus, to a greater extent, our study validates the market power hypothesis, which argues that low competition diminishes firms’ access to finance.