Background:  Body positivity promotion has recently received great attention, both from companies as well as from consumers. The responsibility of companies to promote a healthy body image and be inclusive of all people through their marketing activities is increasing, as the body positivity movement on social media has started to expand and change consumer demands for underwear apparel.                                    Purpose:  The purpose of this study is to examine Swedish female consumers’ online purchasing behavior toward underwear apparel. In order to find explanations as to which factors influence consumer purchase behavior, and what companies can do better, to promote body positivity and make the consumer satisfied.    Method:  The study follows a positivism approach to understand social phenomena and provide explanations through theories.  A quantitative research approach is used by conducting a survey about underwear apparel and body positivity on female consumers. The empirical data is analyzed through a statistical software, SPSS, and the interpretations are guided by the use of the Theory of Planned Behavior (TPB), the MAO framework, background studies, and a conceptual framework developed from the TPB. The conceptual framework includes five added factors to test behavior. Conclusion:  The empirical findings presented positive, statistically significant associations among the introduced factors from the conceptual framework and the purchasing behavior for underwear. The findings also suggest that companies should take a more active role in diversity inclusion in their marketing of underwear, in order to take a step further in their body positivity promotion.