This paper empirically analyzes the main microeconomic determinants of two forms of corruption supply, administrative corruption and state capture, by Maghrebi firms. This study is based on a new database of nearly 600 Algerian, Moroccan and Tunisian firms. I show that tax evasion is a major factor in the engagement of firms in administrative corruption. The latter increases with the share of sales hidden by the firm as long as it is below half of total sales, and slightly decreases thereafter. State capture is fostered by a failing enforcement of property and contract rights. Interestingly, less competitive firms appear to engage more in both forms of corruption than the most dynamic ones. After assessing the robustness of my empirical results, I draw a comparison of the factors of corruption in North Africa, Uganda and transition countries.