Limited research exists on public opinion and understanding of epigenetics. Using an online questionnaire, we investigated the Australian public’s understanding of epigenetics and related concepts, including the concepts of the developmental origins of health and disease (DOHaD). Over 600 questionnaires were completed, with 391 included in the analysis. Data were analysed using predominately descriptive statistics, with free-text responses scored based on concordance with predetermined definitions. While participants’ recognition of epigenetic terms and phrases was high, their understanding was limited. The DOHaD hypothesis was more accurately understood than epigenetics itself. Female participants without children were more likely to recognise the term epigenetics, while age also had an impact. This research provides a solid foundation for further detailed investigation of these themes, all of which will be important data to help inform future public health messages regarding epigenetic concepts.