Background and aims: Sports betting has increased markedly in recent years, in part due to legislative changes and the introduction of novel forms of sports betting (e.g., in-play betting). Some evidence suggests that in-play betting is more harmful than other types of sports betting (i.e., traditional and single-event). However, existing research on in-play sports betting has been limited in scope. To address this gap, the present study examined the extent to which demographic, psychological, and gamblingrelated constructs (e.g., harms) are endorsed by in-play sports bettors relative to single-event and traditional sports bettors. Methods: Sports bettors (N 5 920) aged 18ţ from Ontario, Canada completed an online survey containing self-report measures of demographic, psychological, and gambling-related variables. Participants were classified as either in-play (n 5 223), single-event (n 5 533), or traditional bettors (n 5 164) based on their sports betting engagement. Results: In-play sports bettors reported higher problem gambling severity, endorsed greater gambling-related harms across several domains, and reported greater mental health and substance use difficulties compared to singleevent and traditional sports bettors. There were generally no differences between single-event and traditional sports bettors. Discussion: Results provide empirical support for the potential harms associated with in-play sports betting and inform our understanding of who may be at risk for increased harms associated with in-play betting. Conclusions: Findings may be important for the development of public health and responsible gambling initiatives to reduce the potential harms of in-play betting, particularly as many jurisdictions globally move towards legalization of sports betting.  Kulcsszavak: sports betting, in-play sports betting, single-event sports betting, gambling-related harms