Within the cohort of individuals who seek treatment for disordered gambling, over half fail to complete treatment. The current study sought to identify predictors of treatment dropout in a sample of gamblers attending a residential treatment facility for disordered gamblers in the UK and to report differences in voluntary and enforced dropout. Data on 658 gamblers seeking residential treatment with the Gordon Moody Association (GMA) was analysed, collected between 2000 and 2015. Measurements included demographic data, self-reported gambling behavior, (including the Problem Gambling Severity Index), mental and physical health status, and a risk assessment. Binary logistic regression models were used to examine predictors of treatment termination. Results confirm a high percentage of treatment dropout among disordered gamblers (51.3%). Significant predictors of treatment dropout included older age of the client, higher levels of education, higher levels of debt, online gambling, gambling on poker, shorter duration of treatment, higher depression, experience of previous treatment programmes and medication, and adverse childhood experiences. Within non-completers, significant predictors of enforced dropout included lifetime homelessness, less debt, sports gambling, depression and lifetime smoking. Those who were on a longer treatment programme and had previously received gambling treatment or support were less likely to be asked to leave. Clinicians working in inpatient support need to be aware of the increased psychopathogical and psychosocial problems in those who are at risk of termination and make attempts to retain them in treatment and increase patient compliance.