Abstract Background Messages to prevent gambling harm traditionally focused on individualised responsibility which stigmatise those who experience harm. Shifts have occurred among researchers, advocates, and some governments towards public health approaches which recognise broader determinants of harm. This includes the social practices of gambling and the tactics used by the industry to increase profits. This exploratory study aimed to identify how people who gamble conceptualise the causes of gambling harm. Methods A qualitatively led online panel survey was conducted via Qualtrics. A sample of 427 adults in two Australian states who gamble using electronic gambling machines or sports betting in a typical month provided text responses to the question “What do you think causes gambling harm?”. A reflexive thematic analysis was conducted. Results The vast majority of participants viewed gambling harm as being an issue of personal responsibility or addiction, with some making moral judgements about those who experience harm. Only a small portion of participants recognised the broader determinants beyond the individual that produce harm. Conclusions Gambling is still viewed by people who gamble as an issue of individual behaviour and addiction among a stigmatised sub-group of gamblers. The broader determinants of harm were generally not identified as causes of harm. This suggests the shift towards public health understandings of harm has not extended to the public. There are discrepancies between how the general public understands gambling harm and how it has been conceptualised by experts. Public health messages need to be reconsidered so they are relevant to and understood by the general community. Strategies to shift public understandings of harm also need to be identified. Key messages People who gamble understand gambling harm differently to how it has been conceptualised by experts. This has implications for how harm should be communicated in public health strategies. This study demonstrates the benefits of collecting qualitative data through online surveys.