This study examined factors that predicted discontinuing treatment for gambling problems at pre-treatment, before halfway, and before the end of treatment. Data were from 1,139 Finnish adults who registered in the Peli poikki programme between 2019 and 2021. Peli poikki is an online cognitive behavioural therapy that lasts eight weeks. It involves weekly contact with a therapist. Thus, there is a wait-list period. The researchers found that people were more likely to discontinue treatment if they were younger, had lower education, had more severe gambling problems, were not ready to change their gambling behaviour, had spent longer time on the waiting list, and had fewer good social relationships.