<p>Existing studies, mainly grounded in theories of gender inequality and gender norms, have explained the health advantages that men have over women. However, the role of the internet in gender health inequality remains underexplored. This study integrates the internet access into the existing theoretical framework and develops a comprehensive explanatory model for gender health inequality. Using data from the <i>China Family Panel Studies (CFPS2020)</i>, the analysis identifies that gender, internet access, and gender norms are significant factors influencing mental health. The findings reveal men exhibit a significant mental health advantage over women; however, internet access has a greater promoting effect on women’s mental health than on men’s, thereby narrowing the gender gap in mental health inequality. Gender-equal norms help enhance individuals’ mental health, but the magnitude of this effect is moderated by gender. For women, internet access enhances their awareness of gender equality, which in turn promotes their mental health. However, for men, gender norms mask the positive impact of the internet on mental health. Expanding internet access for women and other disadvantaged groups helps promote gender-equal norms and reduce health inequalities between men and women.</p>