Adolescent alcohol consumption is an ongoing issue of concern. While latest trends indicate an increase in the number of adolescents choosing to abstain from alcohol, there are subgroups within the population who are drinking at alarming rates (Australian Institute of Health and Welfare, 2017). Of late, unforeseen changes of drinking habits due to increased stress and isolation resulting from the corona virus (COVID)-19 pandemic is also of concern (Chodkiewicz et al., 2020; Dumas et al., 2020). The National Health and Medical Research Council (2009) recommends adolescents avoid consuming any alcohol to avoid associated risks and alcohol-related harm. Existing evidence highlights the importance influence of parenting specific behaviours and attitudes on preventing and minimising underage drinking (Yap et al., 2017). Therefore, parent are key targets in strategies to minimise alcohol related risks in adolescents (Newton et al., 2017). Social marketing offers an evidence-based approach to the development of health and social change programs. Social marketing programs have successfully been used to influence positive behaviour change (Kubacki et al., 2017), through the use of social marketing benchmark principles which place the user at the forefront of all behaviour change efforts (Andreasen, 2002). Social marketing literature (Rundle-Thiele et al., 2019, Dietrich et al., 2016) and benchmark principles (French and Blair-Stevens, 2006) emphasise the importance of the generation of user insights and the application of behavioural theories during the formative research process. Co-design is increasingly gaining recognition as an approach to develop innovative and user driven design solutions to some of social marketing most complex issues (Kim et al., 2020). However, co-design approaches may be limited by their exclusion of theory (Dietrich et al., 2017). In fact, while social marketing literature instructs the importance of theory (Rundle-Thiele et al., 2019), in practice theory application is often lacking and superficially reported in existing social marketing literature (Pang et al., 2017, Tebb et al., 2016). Theories may extend program outcomes by focusing on constructs known to cause specific behaviour (Hardeman et al., 2005). Merging inductive and deductive approaches (i.e. user views and theory) is congruent with an abductive approach, thereby allowing insights to be generated by users through a theoretical lens (Meyer and Lunnay, 2013). Thus, this research aims to close the gap between theory and practice through the examination of an abductive co-design process that integrates behavioural theory with user insights during social marketing program design. The thesis commences with a systematic literature review to provide an overview of the current state of evidence and identify key gaps in regards to parent alcohol programs. Three research questions guided Study 1 RQ1: What outcomes do parents experience following participation in parent alcohol programs? RQ2: What is the level of stakeholder engagement in the design process of parent alcohol programs? RQ3: What is the level of theory application in parent alcohol programs? A total of 17 studies detailing 13 individual parent alcohol programs were examined in detail. Findings highlight the potential for parent alcohol programs to positively influence alcohol specific parenting behaviours and attitudes. However, results indicate room for improvement with limited stakeholder engagement during program design and limited levels of theory application and reporting. End users can influence the development of a program through a more audience orientated design such as co-design. Study 2 evaluated a pilot parent alcohol program drawing on insights obtained from co-design research (Hurley et al., 2018), and asked, RQ4: Does a pilot co-designed social marketing program improve alcohol specific parenting factors? A total of 65 parents participated in the pilot program and a repeated measures assessment found that a social marketing program co-designed by parents can deliver positive outcomes for parents, with desired effects observed for all outcomes measured. Given the importance of theory use in social marketing, Study 3 asked, RQ5: Can theory be applied within the seven-step co-design process? Taking an abductive approach, key constructs of Social Cognitive Theory were integrated into co-design activity cards. Following a seven-step co-design process, two co-design sessions were held with a total of 40 participants. Findings demonstrate that theory can be successfully integrated into the six-step co-design process through the use of theory based activity cards. Insights from this study led to the development of a more nuanced approach to co-design that increased the theoretical relevance of co-design outputs. Overall, this thesis contributes to the literature theoretically and practically. Theoretically, this thesis provides evidence to support co-design as an approach to effectively change alcohol specific parenting behaviours. In addition, this thesis contributes to social marketing literature by proposing an abductive co-design approach as a means to develop more user driven and theoretically informed behaviour change programs filling an important gap. Examining co-design through an abductive lens assists social marketing researchers and practitioners in ensuring multiple benchmark principles are applied during program design. Practically this thesis addresses an important problem in present-day society by designing an alcohol education program that is closely aligned with the needs and preferences of the respective target audience.