This research explored adults' perceptions of how sexualized images typically found on social media might influence adolescent girls' mental health, what support girls might need should they experience mental health difficulties, and how such difficulties could be prevented or reduced. Qualitative data were collected using semi-structured in-depth interviews with parents of adolescent girls (n = 11) and those who provide support to them: school support service staff (n = 7) and youth mental health service providers (n = 10) located in Perth, Western Australia. All three participant groups perceived sexualized images typically found on social media as exacerbating poor mental health among adolescent girls. Two interrelated themes, emerged with participants describing the 'potential for comparison' and 'pressure to conform' they believed girls encounter on social media that influences their mental health. Participants also explained how they perceived 'counteracting negative influences' related to sexualized images on social media could prevent or reduce the potential for mental health harms among girls, and the importance of adults and services 'keeping up to date' and being 'approachable and trustworthy' when describing the support they believed girls might need. The findings of this study have important implications for the development of health promotion programs focused on social media use and mental health among adolescent girls.