Disease prevention can be improved with a better understanding of student–environment interactions. The purposes of the study were (a) to compare HIV/AIDS-related knowledge, attitudes, sexual behaviors, and sources of HIV/STI information and (b) to investigate the association between sources of HIV/STI information and HIV/AIDS-related knowledge, attitudes, and sexual behaviors among Chinese college students in China and the United States. Comparative, correlational analysis of survey data from 608 students in two countries was conducted. Chinese students in the United States scored higher on knowledge questions. More students in the United States received HIV/STI information from the Internet and family members than did students in China. Traditional media and schoolteachers had a stronger association with participants’ HIV-related knowledge, age at first intercourse, and number of sexual partners in both samples than did other sources. The survey revealed incomplete knowledge within both groups. Prevention programs should focus on risky misconceptions and should teach about strategic utilization of media.