This study aims to examine the effect of partially and simultaneously the independent variables of brand image, product quality, advertising and country of origin on the dependent variable of purchasing decisions. The population in this study are people who live in Purwokerto City who make purchasing decisions on Maybelline mascara products on Instagram Social Media. The sample selection in this study was done by purposive sampling. Based on the criteria obtained as many as 120 respondents who became the sample. The data analysis technique used in this research is multiple regression analysis. The results of the analysis show that partially brand image has no effect on purchasing decisions, product quality has a positive and significant effect on purchasing decisions, advertising has a positive and significant effect on purchasing decisions, country of origin has no effect on purchasing decisions. Meanwhile, simultaneously brand image, product quality, advertising, and country of origin have a positive and significant impact on the purchase decision of Maybelline mascara products on Instagram social media.