Early identification of HIV by increasing testing is a national priority; however, little is known about HIV testing behaviors in high school age adolescents. We examined the association of individual, partner, and relationship factors with HIV testing using a computer-assisted survey administered from 2003 to 2006 in a community sample of 980 sexually active 14- to 17-year-olds (56% female, 55% Latino, 25% African American) living in a jurisdiction with a high AIDS burden. Twenty percent reported their first sexual encounter as having occurred when they were <13 years of age, 33% had had four or more lifetime sexual partners, 21% reported high partner HIV-risk behavior, and 428 (44%) had been tested for HIV. In our final regression model, independent associations with HIV testing included being female (OR=1.68 [1.23-2.30]), older (OR=1.41 [1.21-1.65]), and having had four or more lifetime sexual partners (OR=2.24 [1.64-3.05]). The strongest independent predictor of HIV testing was having high HIV-related partner communication (OR=3.70 [2.77-4.94]). Being in a serious committed relationship (OR=1.39 [1.02-1.87]) was also independently associated with HIV testing, whereas reporting high worry about HIV/AIDS (OR=0.53 [0.40-0.71]) was independently negatively associated with HIV testing. High HIV/AIDS knowledge, high partner HIV risk behavior, and young age at first sexual encounter were not associated with testing. These findings suggest that, for high school aged adolescents, optimal strategies to promote HIV testing should look beyond increasing HIV/AIDS knowledge and identifying individual risk behaviors to also considering the role of partners and relationships and their influence on testing behavior.