The aim of this study is to examine the impact of digital marketing on consumer behavior in the fast fashion industry in the Kingdom of Saudi Arabia (KSA). The fast fashion industry has been growing rapidly in the KSA, and digital marketing has played a significant role in changing consumer behavior in this industry. The study adopted a quantitative research design and used online surveys as the primary data collection method. The sample consisted of a convenient sample of participants who had purchased fast fashion products in the KSA. The data was analyzed using various statistical methods, including descriptive statistics, correlation analysis, and regression analysis. This study's findings shed new light on how digital marketing has affected customer behavior in the fast fashion sector in the KSA. Consumers in the KSA have a good reaction to digital marketing methods in the fast fashion industry, and this effect is significant.