Bank merger regulation is one of a major subject area that attracts the application and enforcement of the relevant laws from both financial sector and the general competition regulation. The current trend of deregulation, liberalization and privatization hastened the proliferation of banking sector mergers, while the inherently sensitiveness of the sector urges tight regulatory and enforcement institutions on bank mergers. This paper employed qualitative approach to assess the existing substantive and enforcement institutions. Accordingly the study find out that the existing Ethiopian bank merger substantive rules and enforcement institutions suffers from various deficiencies that obstruct the effective regulation and execution of the imminent bank mergers (both voluntary and policy-induced bank merger schemes). The substantive legal frameworks roughly outdated, incomprehensive, haphazardly chopped in different legislations and suffer from loopholes which makes it not capable to effectively deal with the complex and alarming bank merger issues. Likewise, the existing enforcement institutions, lacks a clearly defined guide rules and code of conducts on procedures, jurisdictional interaction, transparency, accountability and cooperation platform among them, which pose a potential risk of regulatory uncertainty, parallel decisions and jurisdictional conflict between and among these enforcement organs. Accordingly, the researcher recommends a need to reform the existing bank merger regulatory frameworks, in line with the well adopted principles and concerns in the regime. Similarly, there is a need to strengthen the existing enforcement institutions and develop cooperation platform among these organs in order to regulate the regime in effective and efficient manner.