The aim of this thesis is to explain user attitudes toward advertising on Instagram. Two forms of marketing communication that we chose to focus on were native advertising and promoted advertising through celebrities. The main goal was to find out which attitudes Instagram users aged 18-35 years had toward these two types of advertising. The data was collected through a quantitative survey, which was conducted digitally on Facebook. Our empirical findings showed us a result that confirmed previous research in the area - that users have negative attitudes towards any type of advertising. We identified minor demographical differences, but the main differences were in the comparison of the two types of advertising. As we analyzed the respondents’ answers through a perspective from the chosen theories, it showed us that users tend to have more positive attitudes towards promoted advertising from celebrities, and more negative attitudes towards native advertising.