Together, men, masculinities and health comprise an emerging area of research, activism and policy debate. International research on men’s health demonstrates how men’s enactment of masculinity may be linked to their sexual health risk. However, little research to date has explored men’s enactment of different forms of masculinity and men’s sexual health from a social generational perspective. To address this gap, insights from Mannheim’s work on social generations, Connell’s theory of masculinity, Butler’s theory of gender performativity, and Alldred and Fox’s work on the sexuality-assemblage, were utilised to offer a better understanding of the implications of masculinities for men’s sexual health. A multi-site cross-sectional qualitative study was conducted in three cities in Bangladesh. Semi-structured interviews were used to capture narratives from 34 men representing three contrasting social generations: an older social generation (growing up pre-1971), a middle social generation (growing up in the 1980s and 1990s), and a younger social generation (growing up post-2010). A thematic approach was applied to analysis to identify the key issues focused upon in men’s accounts. The analysis revealed generational differences and similarities in the construction of masculinity, in sexual practices and in help and health-seeking practices. Findings show that certain ideals of masculinity were common across all social generations. However, social, cultural, economic and political transformations in Bangladesh have produced significant cross-generational differences and discontinuities. Study findings point to the importance of understanding how the production and enactment of specific forms of masculinity are shaped by education, urbanisation, and globalisation, as well as by the cultural dynamics of religion (especially Islam), work, homosociality, patriarchy and heteronormativity, and how these in turn affect sexual health and health-seeking practices. This thesis contributes to a socially located understanding of masculinities, gender and men’s sexual health from a social generational perspective. It argues for the need to move beyond stereotypical, reductionist, essentialist and binary understandings of men, masculinity, gender and health in the South Asian contexts, highlighting opportunities for new forms of intervention and action to promote men’s sexual health.