The prime objective of public transportation is to mitigate the traffic congestion on the road, as it has the ability to cater to a higher number of passengers, which results in a benefit to the environment, since the transportation sector contributes most to air pollution. Efficient and reliable public transportation is desired by many countries, especially those that are facing issues of traffic congestion due to an over-reliance on private vehicles and dense populations in urban areas. Therefore, the aim of this paper is to present an overview of previous studies that have assessed the service quality of public transportation using subjective, objective, and integrated perspectives. Drawing upon a thorough review of existing literature, this study emphasizes key findings and methodologies adapted in evaluating service quality across these perspectives. The subjective approach involves riders’ perceptions, while the objective approach involves the real performance of public transportation, which focuses on the operational attributes. Additionally, the integration between these two approaches provides a more holistic understanding of service quality for which a limited amount of research has been carried out to undertake this study. By exploring the strengths, limitations, and synergies of these different approaches, this paper is able to enhance our understanding of service quality dynamics in public transportation and inform future research directions and policy interventions aimed at improving overall passenger satisfaction and system performance. In addition, accuracy in findings based on this approach is elevated when it comes to a plan for enhancement to elevate the existing service quality.