Background: As an effect of the growth of Instagram during the past few years, more brands have started to use this platform to communicate with their consumers, and a generation that has been shown to be particularly interesting for fast fashion brands, is Generation Y. During the past few years, a term called body-positivity has increased in popularity among social media platforms like Instagram, which purpose is to encourage exposure to different body types. There are several studies that have highlighted the issues regarding the use of exclusively thin models among fast fashion companies, and that this increase body dissatisfaction among women, especially in the Western culture where the ideal is unrealistically thin. This has resulted in criticism towards marketers which have led to some brands starting to use more larger models in their advertising. However, some brands still use exclusively thin models because they believe that this is what people wants to see. Evidently, there are different opinions regarding the subject. However, what has yet not been studied thoroughly is female consumers attitudes regarding the use of body diversity in advertising on Instagram and how this influence brand attitudes and further, their purchase intentions. Purpose: As the authors of this study found a research gap regarding consumers attitudes within the subject – the purpose of this study will be to explore female Generation Y consumer’s insights regarding body diversity in Instagram advertising, resulting in judgment, feelings, and attitudes towards the advertisement and the brand, and how these attitudes influence purchase intentions. The aim is also to explore to what extent the case companies include body diversity in their Instagram advertising. Method: The research purpose was fulfilled by doing an exploratory study, using an abductive research approach and qualitative method. The authors of this study did a semiotic analysis of the advertising content, and further on collected the empirical data by doing 12 semi-structured interviews. The data was further analyzed by incorporating a thematic analysis. Conclusion: The findings of this study showed that Nelly was the only case company including some body diversity in their Instagram advertising. NA-KD and Zalando evoked mostly positive feelings among the participants while Nelly evoked mostly negative ones. Further, the majority of the participants had favorable attitudes and positive purchase intentions towards NA-KD and Zalando. None of the participants had exclusively favorable attitudes towards Nelly’s advertisement, although half of the participants had positive purchase intentions towards the brand. Generally, the majority of all attitudes that were formed towards the case companies were not influenced by the body diversity (or no body diversity) that they were exposed to, but their attitudes were influenced by other things. The results also showed that including body diversity in Instagram advertising is important, for female Generation Y consumers. However, other factors might be more important and furthermore have a greater influence on their purchase intentions, like for example ethnic diversity.