This article provides an evaluation of the effect of the macroeconomic factors on credit risk in Tunisian banks. These factors are mainly the financial liberalization and the monetary policy. The first is manifested through the liberalization of interest rates, competition and the entry of foreign banks. The second, on the other hand, is exerted by the supervising authorities and includes the interest rate, the injection of money and the regulatory ratio. In order to empirically validate this work, we tested the impact of liberalization (concentration index) measured by the degree of penetration of foreign banks in Tunisia, the prudential regulation and the monetary policy on the credit risk in Tunisian banks. A negative relationship between liberalization and credit risk was found. Accordingly, the entry of foreign banks in Tunisia reduces the risk by strengthening the adequacy of the borrowers selection and improving the regulations imposed by the Central Bank of Tunisia (CBT).