TikTok Shop has become one of the fastest-growing social commerce platforms in Indonesia, with Generation Z recorded as its most active user segment. This condition encourages sellers to rely on interactive marketing approaches such as live streaming, brand credibility building, and customer review management to influence purchase behavior. This study examines the effect of live streaming marketing, brand trust, and online customer review on purchase decisions among Generation Z users of TikTok Shop in Semarang City, both partially and simultaneously. A quantitative associative approach was applied using a survey method, involving 96 respondents selected through purposive sampling, namely Generation Z consumers domiciled in Semarang who had made at least two purchases through TikTok Shop within the past six months. Data were collected using a Likert-scale questionnaire and analyzed through multiple linear regression with the assistance of SPSS, preceded by validity, reliability, and classical assumption tests. The results show that live streaming marketing, brand trust, and online customer review each have a positive and significant partial effect on purchase decisions, with live streaming marketing emerging as the most dominant predictor. Simultaneously, the three variables significantly influence purchase decisions and are able to explain a substantial proportion of its variance, while the remainder is explained by factors outside the model. These findings confirm that interactive live content, brand credibility, and peer-generated reviews jointly shape the purchasing behavior of Generation Z consumers in social commerce settings, offering practical implications for sellers on TikTok Shop.