Switzerland has the longest history of the legal practice of non-physician assisted suicide of any country. Assisted suicide is not very tightly regulated in Switzerland, and almost all assisted suicides are supported by a right-to-die organisation. Our study investigates older adults’ attitudes and behaviour towards assisted suicide, and the associations of these with the individuals’ sociodemographic and cultural characteristics, as well as with their own health status and healthcare-related experiences in Switzerland. We performed weighted prevalence and multivariable logistic regression estimation on a nationally representative sample of adults aged 55 and over from wave 6 (2015) of the Survey of Health, Ageing and Retirement in Europe (SHARE) in Switzerland (n = 2168). Overall, 81.7% of respondents supported the legality of assisted suicide, as is currently the case in Switzerland, and 60.9% stated that they would potentially consider asking for assisted suicide under certain circumstances; 28.2% of respondents reported either that they are already or that they are likely to become a member of a right-to-die organisation, with 4.9% of respondents reporting to already be a member of such an organisation at the time of the survey. Higher levels of education and previous experience as a healthcare proxy were positively associated with more favourable attitudes and behaviour towards assisted suicide. Compared to individuals aged 55–64, adults aged 65–74 generally showed more favourable attitudes and behaviour towards assisted suicide. By contrast, religious persons displayed more negative attitudes and behaviour towards assisted suicide. Attitudes towards assisted suicide were also more negative in the oldest age group (75+) in comparison to adults aged 55–64, and among persons living in French- and Italian-speaking Switzerland compared to those living in German-speaking Switzerland. While approval for assisted suicide is high overall in Switzerland, more vulnerable population groups, such as older or less educated individuals, have less favourable attitudes towards assisted suicide. In addition, cultural sensitivities to and personal experiences with death and dying are likely to shape the approval or rejection of assisted suicide as it is currently implemented in Switzerland.