This research aims to study: 1) the demographic factors influencing the customers’ decision and behavior to use the service of Thai massage in Ratchaburi, Thailand; and 2) the influence of service marketing mix factors on the customers’ decision. The study was carried out between May and August 2017. This study employed a quantitative research methodology. The research sample consisted of 400 individuals who had experiences in using Thai massage services in Ratchaburi. A questionnaire was used to collect the data. The data were analyzed by descriptive statistics including frequency, percentage, mean and standard deviation, and inferential statistics. The Research result showed that 1) customers’ decision and their behavior to use the service of Thai massage was influenced by age, occupation, average income per month, and education level; 2) service marketing mix that had an effect on the customer decision and behavior to use the service of Thai massage included, sorted in a descending order, product, process, price, place, personnel, promotion, and physical attributes.
Keywords: Service Quality, Customer Expectation, International Tourists