This study highlights the important dimensions of service quality from customers’ perspective in car service agencies. Additionally, it aimed to identify differences between expectations and perceptions of customers from service quality dimensions and compares differences across agencies. The objectives of this study were achieved by using the SERVQUAL questionnaire. A cluster sampling technique was also used for collecting the data. The questionnaires were distributed amongst 400 customers who had Peugeot 206, Peugeot 405 or Peugeot Persia in four Iran Khodro car service agencies. The results demonstrated that there was a gap between expectations and perceptions of customers from dimensions of service quality. The negative gaps were related to the intangible dimensions. Additionally, in the comparison amongst four agencies related to the level of expected service quality, significant differences were found for tangibles and reliability dimensions. Furthermore, the analysis of variance revealed that the differences in customers’ perceptions of the level of provided service quality across four agencies was only for the dimension of tangibles. Lastly, the findings demonstrated that there were significant (p