OBJECTIVE To determine the prevalence of violent behaviors among Mexican-American and non-Hispanic white high school students and to explore the associations between violent behaviors and alcohol and illicit drug use. METHODS The Youth Risk Behavior Survey was administered to 1786 high school students in a biethnic community in Southeast Texas; 65% were Mexican-American, 26% were non-Hispanic white, and 9% were of another ethnicity. RESULTS There were no significant ethnic differences in prevalence of drinking alcohol, illicit drug use, fighting, carrying a weapon, or planning or attempting suicide. After adjustment for age, carrying a weapon and fighting were significantly associated with alcohol and illicit drug use, with few exceptions, among the four gender- and ethnic-specific subgroups. However, the relationship between suicide (plans and attempts) and substance use among the four subgroups was less consistent and of much lower magnitude than for carrying a weapon and fighting. CONCLUSIONS A substantial percentage of adolescents engage in violent behaviors, and fighting and weapon carrying are associated with substance use among both gender and ethnic groups. A systematic and integrated approach to changing the environment and norms of communities is needed to affect change and reduce the morbidity and mortality associated with violent behaviors.