Since its development in the late 1980s, the Male Role Norms Inventory (MRNI) and related forms have been used in 91 studies to examine masculinity ideologies through male role norms in the United States and other countries with over 30,000 participants. The study of male role norms and masculinity ideologies has remained a prominent area of study in the psychology of men and masculinities since at least 1995. Since the last formal review of the MRNI in 2007, 2 new forms of the MRNI have been developed, including short form and adolescent versions, and various forms of the measure have been used in at least 70 additional studies. After describing the development and psychometric properties of the MRNI, this article reports the results of a content analysis of all studies on male role norms using the MRNI in all forms, describing sample demographics, methodologies, topics, and findings. Results of the present study show the MRNI has been used to investigate men’s psychological, physical, and sexual health, romantic relationships, quality of friendships, and vocational decisions. The MRNI has also been utilized in examining negative attitudes toward People of Color and sexual minority and gender nonconforming men. This content analysis also highlights understudied areas such as body image, sports, religiousness/spirituality, and fatherhood. Finally, it calls for more representative samples in terms of ethnic, racial, sexual orientation, and gender diversity. Implications for clinical applications of previous findings are discussed and recommendations for further investigating male role norms and masculinity ideologies research are presented. (PsycINFO Database Record (c) 2018 APA, all rights reserved)