This study explores the determinants of the financial performance and sustainability of Moroccan Microfinance Institutions (MFIs). Through the use of panel data concerning 10 MFIs (available on the MIX platform) with different time frames, three OLS models are run and aim to explain MFIs financial performance and sustainability using independent variables related to the size of the MFIs, the quality of their loan portfolios, the degree of outreach, and their productivity. The results obtained show that: (1) the personnel productivity contributes significantly to the MFIs’ Return on Assets and their sustainability, and (2) the loan repayment level of MFIs customers is an important determinant of their sustainability.