Background: Campaigns highlighting the health harms of smoking have demonstrated success in motivating people who smoke to quit. Tobacco production and use also exert a toll on the environment, sustainable development and human rights. However, messages highlighting these harms of tobacco have been relatively unexplored as a cessation motivation strategy. In this study, we examined the extent to which a range of messages about climate, pollution and social justice harms of tobacco are perceived as motivating among people who smoke, overall and by sociodemographics., Data and Methods: Australian adults who smoke (n=395) aged 18-59 years reported the 'extent to which each of the following motivated them to quit smoking' and were then presented with messages about climate (four items), pollution (three items) and social justice (three items) harms of tobacco, which they rated on a 5-point scale ranging from 1 'Not at all' to 5 'Very much so' in this online cross-sectional survey. Differences by age, education, gender, socioeconomic status (SES) and geographical region were examined using prevalence ratios from generalised linear models with log-link (Poisson regression)., Results: For each of the 10 messages, between one-half and two-thirds of the overall sample perceived them as motivating (49-65%), particularly messages highlighting harms to human or animal life and welfare (all ≥60%). Across all message themes, younger adults (18-35 years) and those who completed tertiary education were more likely to perceive some messages as motivating. Perceived motivation did not vary significantly by gender, SES or geographical region., Conclusion: Findings suggest that value-based messaging featuring the environmental and social justice footprint of tobacco is perceived as motivating for smoking cessation, especially among younger people and those with higher education who may be more engaged with these issues. Inclusion of such messages as part of a comprehensive antitobacco communication strategy may provide an untapped opportunity by potentially providing people who smoke with additional compelling reasons to quit., Competing Interests: Competing interests: TT, EM, TN and SJD are employed by a non-profit organisation that conducts public health interventions and advocacy aimed at reducing the harms of tobacco in the community, especially those pertaining to cancer., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)