Introduction: Regular serves of alcohol and repeated episodes of intoxication in adolescence are linked with increased risk of alcohol dependence and other social and health inequalities in adulthood. The Australian Guidelines to Reduce Health Risks from Drinking Alcohol (National Health and Medical Research Council (NHMRC), 2009) suggest that abstinence from alcohol is the safest option for young people under the age of 18 years, and that for those aged 15-17 years, it is preferable to delay initiation. For under-age Australian adolescents, parents are the most common source of supply of alcohol. However, there is a dearth of research on parents‟ beliefs and practices in relation to the supply of alcohol to young people. Aim: The aim of this study was to determine the extent to which parent and adolescent characteristics may influence Australian parents‟ beliefs and practices in relation to the supply of full serves of alcohol (i.e., not simply sips) to their adolescent aged 14-16 years and their adolescents‟ attendance at parties where alcohol is available. Method: A cross-sectional sample of 388 Victorian parents of 14-16 year olds, registered with a market research company, completed an online survey about parental supply of alcohol to their adolescent and adolescents‟ party attendance. Parametric and non-parametric equivalent inferential statistics were used to measure associations between parental supply of alcohol and parental beliefs, behaviours and parent/adolescent socio-demographic characteristics. Linear and logistic regression was used to measure the association between parental supply of alcohol, adolescent attendance at parties, the supply of alcohol in such settings, and multiple independent variables. Results: Seventy percent of parents reported that that their adolescent may/does currently drink. Of these, 37% reported supplying their under-age adolescent with more than a sip of alcohol in the last three months. Alcohol supply was significantly positively associated with parents‟ perceptions that their adolescent drinks and higher levels of parental monitoring but was not significantly associated with parent/adolescent socio-demographic characteristics or parents‟ self-reported drinking patterns. Parents‟ plans to supply alcohol to their adolescent in the next six months were significantly positively associated with their reports of supplying alcohol in the last three months, perceptions that their adolescent drinks, parents‟ reports of not practising religion, and parents‟ alcohol consumption scores as measured by the Alcohol Use Disorder Identification Test (AUDIT) (Saunders, Aasland, Babor, De la Fuente, & Grant, 1993). Forty-one percent of parents reported that their adolescent had attended a party in the last three months. Of these, 34% reported that their adolescent had been supplied with alcohol. Adolescents‟ friends were reported as the most common source of supply followed by parents. While 70% of parents reported that they were likely to contact the parents hosting a party, only 32% said they actually did so. Party attendance was significantly positively associated with parents‟ perceptions that their adolescent drinks, parents‟ beliefs about adolescents‟ access to alcohol and parents‟ AUDIT scores. Supply of alcohol at a party was significantly positively associated with parents‟ perceptions that their adolescent drinks, that their adolescents‟ friends drink and parenting a „middle‟ child. Discussion and conclusion: Consistent with reports from Australian students, parents are a major source of supply of alcohol to under-age adolescents. Parents‟ perceptions of their adolescent‟s drinking are a significant predictor of parental alcohol supply and adolescent alcohol use at a party. Parents report higher levels of monitoring when supplying their adolescent with alcohol. This may be a reflection of alcohol supply in the family home where many parents sanction the use of alcohol in the belief that this will teach their adolescent to “drink responsibly.” Parties represent “high-risk” alcohol use environments but few parents could be expected to be aware of recent neurobiological research that links changes in the brain at adolescence to increased sensation-seeking behaviour, particularly when in the company of peers. Parents‟ beliefs about adolescents‟ attendance at parties and the supply of alcohol to adolescents may be mediated by broader social and environmental factors (e.g., price and ease of availability) that contribute to the normalisation of alcohol use by adolescents. While there are legislative and policy guidelines regarding the use of alcohol by underage adolescents, there is arguably a need for policy change and national guidelines for parents, embedded in the broader social context and consistent with the Australian Alcohol Guidelines (NHMRC, 2009), to support parents in implementing strategies to reduce their adolescent‟s exposure to alcohol-related harm.