This study proposes a comprehensive model of the process by which perceived waiting time affects consumers' service quality evaluations, exploring the roles of acceptability and negative emotions as mediating variables and the factors that perform moderating functions on each mediating variable, and empirically tested this model in the context of hospital services. According to the path analysis results, it was confirmed that negative emotions and acceptability serve as mediating variables in the process through which perceived waiting time influences service evaluations. Furthermore, it was found that between these two mediating variables, acceptability has a stronger influence on customers' service evaluations. Additionally, acceptability was confirmed to play the most critical mediating role, as it exhibited a stronger correlation with perceived waiting time than negative emotions did. Moderated regression analysis was conducted to explore the factors performing moderating roles in the respective relationships between perceived waiting time and negative emotions, and between perceived waiting time and acceptability. The results revealed that for negative emotions, expectation disconfirmation, transaction importance, persistence of waiting causes, and waiting environment were significant factors, while for acceptability, only transaction importance and expectation disconfirmation were found to be significant factors. Whereas prior studies had limitations in specifically elucidating the process by which waiting time affects service quality evaluations—as they merely conducted simple correlation analyses between individual variables rather than examining the process through an integrated model, thereby failing to distinguish the roles of each variable—the significance of this study lies in its comprehensive explanation of the overall process by differentiating the roles performed by each variable.