Social media/social networks (SM/SNs), while ubiquitous in their use, have not been well integrated into psychological theory or practice. Most research addressing SM/SNs has examined frequency and modality of SM/SN use, rather than the valence of online interactions or potential mental health consequences of use. Further, SM/SN use has also not been well integrated with relevant paradigms from the psychology of men and masculinities paradigms. The present study contributes to both of these research need areas by testing the associations among SM/SN use, toxic masculinity, positive or negative SM/SN interactions, and depression among a sample of 402 men. Results of a structural equation modeling analysis indicated that SM/SN use and toxic masculinity were associated with depression. Positive and negative SM/SN interactions mediated the relationship between SM/SN use and depression indicators, and negative SM/SN interactions mediated the relationship between toxic masculinity and depression. Implications for future research directions and for working with men who use SM/SNs are discussed.