Purpose: Young Australian workers are at elevated risk of mental health and alcohol and other drug related problems. The purpose of this paper is to examine the relationship between alcohol and drug (AOD) use, psychological wellbeing, and the workplace psychosocial environment among young apprentices in the construction industry. Design/methodology/approach: A cross-sectional survey of a cohort of 169 construction industry apprentices in their first year of training was undertaken. The survey included measures of psychological distress (K10), quantity/frequency measures of alcohol and illicit drug use, and workplace psychosocial factors. Findings: Construction industry apprentices are at elevated risk of AOD related harm and poor mental health. Levels of psychological distress and substance use were substantially higher than age/gender equivalent Australian population norms. Job stress, workplace bullying, and general social support accounted for 38.2 per cent of the variance in psychological distress. General social support moderated the effects of job stress and bullying on psychological distress. Substance use was not associated with psychological distress. However, workplace social support accounted for 2.1 per cent of the variance in AUDIT-C scores, and 2.0 per cent of the variance in cannabis use. Workplace bullying explained 2.4 per cent of the variance in meth/amphetamine use. Practical implications: Construction trades apprentices are a high-risk group for harmful substance use and poor mental health. Study results indicate that psychosocial wellbeing interventions are warranted as a harm reduction strategy. Originality/value: This is the first study of its kind to describe a cohort of Australian construction trade apprentices in terms of their substance use and psychological wellbeing. The study shows workplace psychosocial factors may predict young workers psychological wellbeing.