Background Interventions are needed to prevent and mitigate unhealthy commodity industry (UCI) influence on public health policy. Whilst literature on interventions is emerging, current conceptualisations remain incomplete as they lack considerations of the wider systemic complexities surrounding UCI influence, which may limit intervention effectiveness. This study applies systems thinking as a theoretical lens to help identify and explore how possible interventions relate to one another in the systems in which they are embedded. Related challenges to addressing UCI influence on policy, and actions to support interventions, were also explored. Methods Online participatory workshops were conducted with stakeholders with expertise in UCIs. A systems map, depicting five pathways to UCI influence, and the Action Scales Model were used to help participants identify interventions and guide discussions. Codebook thematic analysis was used to analyse the data. Results Fifty-two stakeholders participated in ۲۳ workshops. Participants identified ۲۷ diverse, interconnected and interdependent interventions corresponding to the systems map’s pathways that reduce the ability of UCIs to influence policy. These include, for example, reform policy financing; regulate public-private partnerships (PPPs); reform science governance and funding; frame and reframe the narrative, challenge neoliberalism and gross domestic product (GDP) growth; leverage human rights; change practices on multistakeholder governance; and reform policy consultation and deliberation processes. Participants also identified four potential key challenges to interventions (ie, difficult to implement or achieve; partially formulated; exploited or misused; requires tailoring for context), and four key actions to help support intervention delivery (ie, coordinate and cooperate with stakeholders; invest in civil society; create a social movement; nurture leadership). Conclusion A systems thinking lens revealed the theoretical interdependence between disparate and heterogenous interventions. This suggests that to be effective, interventions need to align, work collectively, and be applied synchronously to different parts of the system, including multiple levels of governance. Importantly, these interventions need to be supported by intermediary actions to be achieved. Urgent action is now required to strengthen healthy alliances and implement interventions
