This study investigates the customers' expectation and perceptions of service quality delivered by restaurants in Shiraz and its effect on customers' satisfaction and loyalty. By clustering sampling method, 450 customers of the restaurants located in all nine districts of Shiraz were selected and the data was collected from the respondents by means of a questionnaire. From the results it was found that customers' expectation yielded a significant effect on the customer's perceived quality and loyalty. Although, the effect of customers' expectation on the customers' satisfaction was not statistically supported. Moreover, it was discerned that the customers' perceived quality toward the service had a significant effect on the customers' satisfaction and customers' loyalty. Finally, the result demonstrated the existence of a significant influence imposed by the customers' satisfaction on the customers' loyalty.