The supermarket industry is characterized by intense competition, which has become more intense during recent times since new players are entering the market, private labeling products have increased their market share, and the range of choices available to buyers is rapidly expanding. This motivates supermarket owners to focus on customer-oriented strategies so that they are able to differentiate from the competition. Within the marketing strategy of firms, the element of customer satisfaction maintains a superior position since it can reinforce store loyalty and lead to the creation of significant market power. This paper examines supermarkets’ customer satisfaction based on various factors, such as Products, Pricing Policy, Private Labeling, Stores, Staff, Customer Information and Service. Data were collected by applying a structured questionnaire to a convenient sample of 300 supermarket customers in the area of Athens, Greece. The research outcomes were analyzed with the Multicriteria Satisfaction Analysis (MUSA) method. MUSA is an analysis methodology developed on the principles of regression analysis. Results highlighted the crucial role of the human element and the availability and quality of the product in the overall satisfaction of supermarket customers. Those aspects should be further improved for reinforcing customer loyalty and commitment, as well as for increasing the perceived satisfaction of supermarket customers in the process.