In recent years, zero-emission technologies in public transport have developed rapidly, particularly in the electrification of bus fleets. Amid global efforts to reduce CO2 emissions and improve urban air quality, the economic viability of electric buses compared to conventional diesel counterparts has become an increasingly important issue. The existing research presents diverse approaches to the economic efficiency of these technologies, making definitive conclusions difficult. This article addresses this issue by providing a systematic literature review on the economic efficiency of electric and diesel buses, with a particular focus on the total cost of ownership (TCO) methodology. It identifies the key factors influencing research outcomes and highlights the major methodological limitations, offering valuable insights for future investment decisions and transport policy development. Additionally, the article seeks to answer the following research questions: RQ1-Is there a consensus in the scientific literature regarding the superior or inferior economic efficiency of electric buses compared to conventional buses? RQ2-Which types of urban buses are most commonly used as benchmarks in economic efficiency analyses of electric buses? RQ3-What assumptions are made when analyzing the economic efficiency of electric buses relative to conventional buses? RQ4-How do key economic variables differ across various studies? RQ5-What are the main methodological and empirical limitations in economic efficiency analyses of urban buses? By synthesizing and integrating the findings from multiple studies, this review provides a comprehensive perspective on the cost-effectiveness of electric buses. The results and conclusions contribute to the academic discourse on sustainable mobility, offering valuable insights that deepen the understanding of costs associated with electric public transport. Additionally, this review provides practical information for public transport operators and policymakers, supporting more effective strategic planning of fleet electrification.