The image-centric nature of Instagram has contributed to the rise of a prominent social media trend known as “fitspiration.” Previous research has shown that exposure to fitspiration content on Instagram can have detrimental effects on body image and mental health, particularly among young heterosexual women. Although sexual minority individuals may similarly be subjected to the objectifying gaze, there is a dearth of research regarding how they perceive and respond to fitspiration content. This study investigates the effects of consuming fitspiration content on Instagram on self-objectification and depression symptoms among sexual minority individuals and explores how gender and sexual orientation interact to shape their body image experiences. A total of 551 sexual minority individuals participated in the study. The results showed that viewing fitspiration content, but not the general use of Instagram, was positively associated with body surveillance and body shame. The association between fitspiration content consumption and depression symptoms was mediated by body surveillance and body shame. The study shed light on the influence of gender and sexual orientation, revealing significant mediation effects among gay men, plurisexual men, and plurisexual women; however, these findings were not observed among lesbian women. Given the substantial burden associated with fitspiration use, social media developers, content creators, and clinicians have a vital role to play in cultivating a body-positive online environment and protecting sexual minority individuals from internalizing objectifying content on social media.