Gender equality is a key target for conservation but is often treated as a women's issue with limited attention to the roles of men and masculinities in perpetuating unequal gender relations. This paper provides a qualitative systematic review of academic literature on “masculinities”—actions, norms, and values associated with men—in the conservation sector and synthesizes the reported effects of masculinities on conservation science, policy, and practice. We adopt a performative and intersectionality-inspired approach, recognizing that masculinities may be performed by men, women, nonbinary, and gender-diverse people, and that gender interacts with other dimensions of identity such as race, age, and (dis)ability. We found that the current literature primarily reports conservation masculinities performed by White men in Global North and settler-colonial contexts. The most common actions and norms were the exercise of control/authority, rationalism, and strength, and the most common effects were the marginalization of others, prioritization of natural sciences over other knowledge, and support for policies such as protected areas and militarization. Explicitly addressing the dominance of such masculinities, as well as the conditions through which their dominance is enabled and rewarded, may contribute towards gender equality and to more just and effective forms of conservation.