This dissertation consists of two empirical papers that explore recent phenomena in Banking and Microfinance Performance. Chapter 1, “Market Power and Bank Performance in MENA Countries,” examines the determinants of market power in 12 Middle Eastern and North African (MENA) countries in the aftermath of the Global Financial Crisis (GFC), specifically within six Gulf Cooperation Countries and six non-Gulf countries. We examine the dynamics of bank competition in MENA countries, provide an up-to-date assessment of market power, investigate the factors impacting bank competition, and explore the evolution of market power during the financial crisis. Our results show an overall increase in market power following the GFC for both regions. We find that bank size, capitalization, and diversification affect market power differently in the pre-crisis and post-crisis years. Larger banks enjoy cost advantages and the diversification impact on market power has decreased in the post-crisis years and the impact of capitalization on market power increased during the GFC. Overall, banks with higher capitalization can better weather the crisis. Chapter 2, “The impact of firm-level characteristic and county-specific attributes on the performance and efficiency of the Microfinance institutions,” estimates the impact of country-specific macro-variables and firm-specific attributes on the financial performance and the efficiency of microfinance institutions (MFIs). We use a large international up-to-date database consisting of over 10,000 firm-years for MFIs over 89 countries during the period 2008-2015. Several interesting findings emerge: a) regulation and outreach are negatively correlated. b) There is a negative and highly statistically significant correlation between the percentage of female borrowers and loan size, which is evidence of “mission drift”. c) An increase in the percentage of female board member has positive and statistically significant effect on MFIs profitability and ROA; which emphasizes the importance of female participation in leading position in MFIs.