The objective of this final project is to determine the influence of brand extension and product quality on consumers’ buying decision Antimo Eucalyptus Oil (Case Study in Promotion Event of PT. Phapros, Tbk Semarang Branch). The method for doing the research is regression analysis. The method used in the research is multiple liniear regression analysis. The sampling technique used in this study is purposive sampling. The samples are 50 respondents. Methods of data collection are interviews, questionnaires and literature review. The result of this study is that the calculation of regression model obtained Y= 5.804 + 0.299X1 + 0.448X2. It means that the result of regression give positive influence on consumers’ buying decision, and the influence of product quality on consumers’ buying decision is greater that brand extension. The result of analysis showed that all variables of this research were positive because the significance was less than alpha (0.05) and tcount > ttable. It can be seen that tcount of brand extension variable was 2.087 and the signification value was 0.042. Then, tcount product quality was 4.164 and the signification value was 0.000. Based on analysis result, this two independent variables had influence on consumers’ buying decision. Because Fcount (12.099) > Ftable (3.20). Coefficient determination is 0.340, it means that 34% of consumers’ buying decision could be explained by the brand extension and product quality. Meanwhile, the rest of the 66% is influenced by other variables which are not included in this study.