This cross-sectional study aims to examine the prevalence and correlates of harmful alcohol use among aboriginal people in southern Taiwan and to examine the associations between harmful alcohol use and adverse drinking effects. Four hundred forty-nine aboriginal adults were recruited from two townships in southern Taiwan to complete the questionnaires. Among the aborigines, 59.7% scored an 8 or above on the Alcohol Use Disorders Identification Test, including 26.7% who were found to be hazardous drinkers (AUDIT level II), 18.5% who were harmful drinkers (level III), and 14.5% who were with likely dependence (level IV). Male aborigines who participated less in religious activities, had stressful life events, were cigarette smokers, or were betel quid chewers were more likely to have harmful alcohol use. Harmful alcohol use was also associated with an inability to work and with arguments with other people. Our study suggests that aboriginal people in southern Taiwan experience alcohol-related risks at rates as high as other worldwide populations for which AUDIT results are available. Individuals with AUDIT scores at levels II and III are generally candidates for brief interventions delivered in generalist health settings. Individuals with AUDIT scores at level IV should be referred for an addiction specialty evaluation and possible treatment as well as lower-risk individuals (those with AUDIT levels II–III) if they have concurrent physical or psychiatric disorders.