Several evaluation standards and performance indicators have been developed to determine transit performance at a system, regional, or national level. Performance indicators that are traditionally used to evaluate transit systems are ratios of a service output to a resource input or a service consumption measure. This paper discusses a method that evaluates the relative performance of a group of transit systems considering multiple input and output measures. The proposed method is not intended to provide a conclusive evaluation of transit systems, rather to answer the question of how efficient is each of the transit systems analyzed, relative to the other systems considered in the analysis, in terms of allocating resources to provide service. For a selected group of bus transit systems, the proposed procedure is used to identify both technical and scale inefficiencies, meaning inefficiencies related to the production and consumption of service, and to disadvantageous operating conditions. The most efficient systems within the group are identified, while for the remaining systems the types and sources of inefficiency are determined. The procedure is based on data envelopment analysis, a relatively new area in the field of operations research and management science.