We examined emerging adults (EAs) motivations against sex (MAS) and how these related to their self-reported sexual behavior. Study 1 examined the relationship between demographic variables and three MAS. Study 2 examined the relationship between MAS and the number of sexual partners (LSP). In Study 1, less permissive casual sex attitudes were associated with all MAS. Women and those with less sexual experience endorsed value and not ready motives. In Study 2, those endorsing value and not ready motives had fewer LSP, but those who endorsed health motives reported more LSP. Results hold implications for EA sexual health education.