The purpose of this paper is to develop assessment framework for customer loyalty in quick-service restaurants. Building customer loyalty is a key factor in influencing repeat purchases in the designated restaurant. This framework used multi-grade fuzzy for assessment and importance performance analysis is used to identify the weaker attributes that need to be improved. The case study has been conducted in a quick-service restaurant. Based on the case-analysis promised and on-time service, attentive staff, and a range of foods are weaker attributes. This framework enables restaurant managers to identify and improve customer satisfaction, which will have a direct influence on customer loyalty.