Objectives:To analyse associations within the UK public between vaccine-related attitudes and knowledge about the role of antibiotics for treating various infections. Design:Secondary analysis of a random-probability mixed-mode survey conducted by NatCen Social Research for the Wellcome Trust in late 2018.Setting:England, Wales, Scotland.Participants:2,708 members of the public recruited to the NatCen Panel from the British Social Attitudes random-probability survey.Main outcome measures:Ordinal logistic regression models of antibiotic-related knowledge predicted by vaccine attitudes, controlling for age, sex, education, employment status, geography, health information habits, perceptions of individual agency, and interview mode. The outcome variable was based on a question about the kinds of infections antibiotics are useful for treating. Vaccine-attitude outcomes were perceptions of the risk of serious side-effects from vaccination and perceptions of the efficacy of vaccination as a preventative intervention. Results:Compared to the modal response category of ‘Fairly low’, respondents who rated the risk of serious side-effects from vaccination as ‘Very high’ (OR=3.34, 95% CL=2.13-5.25) or ‘Fairly high’ (OR=1.55, 95% CL=1.26-1.90) were more likely to have provided incorrect responses to questions about the utility of antibiotics for treating different types of infection. Conversely, respondents who felt that there was ‘No risk at all’ (OR=0.64, 95% CL=0.46-0.87) were less likely to have provided incorrect responses about the utility of antibiotics. Compared to the modal category of ‘Almost always effective’, respondents who felt that vaccines were ‘Sometimes effective’ (OR=1.25, 95% CL=1.05-1.49) as a preventative intervention were slightly more likely to have provided incorrect responses regarding antibiotics’ utility. However, there were no other significant associations between perceptions of vaccines’ efficacy and knowledge about antibiotics. Conclusions:Perceptions of the risk of side-effects from vaccination and their understanding of the role of antibiotics for treating different infections are associated with one other within the general UK public. Research is needed to understand the nature of this association and identify areas of public understanding that are not exclusive to specific health interventions but that may be targeted to improve responsiveness to vaccine- and antibiotic-related public health interventions.