A growing body of research suggests that free heterosexual internet pornography (IP) often depicts violent, coercive, and degrading acts by men against women. This has raised concerns that IP may be fostering the development of gendered, coercive, and aggressive sexualized beliefs and attitudes toward women, with the potential for these to influence how some men behave in their sexual interactions with women. The current study of young adult males and females (17–25 years) explored problematic IP viewing and how this might be associated with the development of gendered and sexually aggressive attitudes. Specifically, a number of environment and person factors that might lead individuals to be more susceptible to the development of problematic IP viewing, and the endorsement of gendered and sexually aggressive beliefs and attitudes were examined. Positive associations were found between problematic IP viewing, stereotypical gendered attitudes, IP-congruent beliefs (including beliefs that endorse sexual coercion), and psychological vulnerability factors such as higher levels of sexual impulsivity, depression, and the tendency to dissociate. Higher stereotypical gendered beliefs, higher IP-congruent sexual beliefs, and higher sexual impulsivity all uniquely contributed to the prediction of problematic IP viewing. Based on these findings, it appears probable that some young adults’ sexual attitudes and beliefs may be, to some extent, associated with their exposure to the violent, coercive, and degrading acts by men against women often found in IP. Broader implications for aggression and violence against women are discussed.