This study investigates how Instagram’s affordances enable social surveillance, as well as the motivations, behaviors, and effects associated with youth engagement in surveillance practices. While existing research has examined the behaviors and effects of social surveillance, there is limited empirical work on how platform design enables monitoring. Moreover, few studies have adopted a multi-method approach. Using a combination of a walkthrough analysis of Instagram’s design, guided tour interviews, and a survey, this study addresses these gaps. The walkthrough analysis found that Instagram encourages social surveillance through its emphasis on interconnectedness and network formation. Interviews provided in-depth insight into how users navigate platform affordances—for visibility, persistence, and anonymity—to engage in surveillance, with key motivations emerging around romantic interest, curiosity, and inspiration. Effects included feelings of FoMO (fear of missing out) and jealousy. The survey results showed that social surveillance is a widespread behavior among youth, with female participants engaging more frequently than male participants. Key motivations cited by survey respondents included staying updated and romantic interest, while reported emotional effects ranged from neutral to negative. Informed by these three studies, this thesis demonstrates that social surveillance on Instagram is not incidental but structurally embedded within the platform’s design. Affordances around visibility, anonymity, and persistence enable ongoing, often emotionally charged monitoring behaviors—particularly in romantic and social contexts. Motivated by curiosity, uncertainty, and comparison, users engage in recursive cycles of observation. This ongoing cycle is not incidental but strategically embedded into Instagram’s design, sustaining perpetual engagement in line with the platform’s business model.