The purpose of this study is to examine the effect of product quality, price, and promotion on customer loyalty on Smartfren prepaid card users in Denpasar City. This research was conducted in Denpasar City by using a sample size of 100 people with a probability sampling method. Data collection was obtained by the results of questionnaires using a scale as measured by a Likert scale. The data analysis technique used in this study is multiple linear regression analysis techniques. The results of the study proposed that product quality has a positive and significant effect on customer loyalty in Smartfren prepaid card users, prices have a positive and significant effect on customer loyalty, and promotion has a positive and significant effect on customer loyalty on Smartfren prepaid card users in Denpasar City. Keywords: product quality, price, promotion, customer loyalty