Accessibility of transport services can be influenced by a range of factors, and it is important to understand the role and influence of each of these factors in order to plan effective transport systems in urban, peri-urban and regional settings. Addis Ababa City is one of the fastest growing cities in the world, yet is constrained by poor accessibility of city bus transport services. This creates problems relating to journeys to work, school and other travel. This paper examines the factors affecting the accessibility of Anbessa City bus service in Addis Ababa. An exploratory research approach was taken, using in-depth interviews with the city bus transport regulators as well as one operator. The study identified eight principal factors impacting on the accessibility of the bus services, these being infrastructure conditions, stakeholder engagement, law enforcement system, user accessibility, institutional frameworks, transport operations, transport planning, and comfort and safety of the transit system. Identifying these themes should assist in implementing future improvements to the accessibility of bus service, thus providing more effective transport options for the residents of Addis Ababa and its peripheral regions.