This chapter explores how, in cultures where male power is hegemonic, claiming and mobilizing a masculine identity and avoiding the feminine can become problematic for environmental sustainability. I begin with basic tenets of critical gender theory and masculinities studies that help explain the relationship between masculinity and environment. I then examine recent research suggesting that anti-environmental attitudes and behavior as well as indifference or skepticism about environmental science and risk can be explained in part as performances enacted to signal a masculine identity. After discussing these direct anti-environmental masculine performances, I explore how enacting core masculine-coded performances not directly related to the environment can also obstruct environmental protection. Privileging the rational, technical, and competitive, and avoiding feminine-coded emotion and cooperation can result in excluding social justice arguments for environmental action and favoring technological and business-friendly solutions that may be untested and dangerous – such as climate geoengineering – over vital regulations and multi-lateral cooperation.