This study investigated the social ecology of substance use among 162 tertiary students studying at Northern Territory University in April 2000. The sample was predominantly female (69.6%), Australian born (70%), non-Indigenous (77.2%), not active in the labour market (58.8%) and intending to complete an undergraduate degree (62.7%). Substance use was prevalent, and 77.6% of students were current drinkers, 59.4% currently smoked tobacco and 28.5% used other drugs. Polydrug use was evident, with 24.8% of students using more than one substance on the same occasion in the previous month. Substance use tended to be associated with relaxing, socialising and wanting to feel good. Most students were not concerned about their alcohol use and their perceptions of normal drinking behaviour highlight the challenges in addressing substance misuse patterns in this population.