This study aims to investigate the relationship between consumers' social media addiction (SMA) levels and their online purchasing intentions (OPI) while examining the mediating role of attitudes towards online advertisements (ATOA) in this relationship. Additionally, the study aims to explore whether the demographic characteristics of consumers influence their levels of SMA, ATOA, and OPI. An online questionnaire consisting of the ATOA, SMA, OPI scales and demographic characteristics was shared with 402 participants using convenience sampling. Confirmatory factor analysis and structural equation modelling were applied to the data. T-tests, ANOVA, Levene, Tukey, and Tamhane T2 tests were used for difference analysis. According to the results, social media addiction positively affects the attitude towards online advertising and purchase intention. There is a partial mediating effect of the attitude towards online advertising in the effect of social media addiction on online purchase intention. Discriminant analysis results show that social media addiction is higher among single students between 18 and 25. While the attitude of young and single students towards online advertisements is more positive, the attitude towards online advertisements is more negative in consumers aged 36 and over compared to other consumers. Online purchase intention is higher in female consumers with a bachelor's degree or higher education level and lower in consumers over 36 years of age with a low-income level. Thus, it is recommended that practitioners focus on this target group in online advertising.