As the popularity of internet gambling increases, the increased opportunities to participate serve to heighten concerns about the potential for gambling related harm. This paper focuses on self-exclusion as one of the main responsible gaming interventions, and is split into three sections. Firstly, we set out a three-tier model for assessing at-risk gambling behaviors which examines player exhibited, declared and inferred behavior. Secondly, we present a literature review relating to who self-excludes and whether self-exclusion is effective. Finally, we report the results of an analysis of the exhibited behavior of internet self-excluders as sampled from a research cohort of over 240,000 internet gaming accounts. Our analysis of self-excluders (N = 347) versus a control group (N = 871) of gamblers indicates self-excluders are younger than the control group, more likely to suffer losses and more likely to adopt riskier gambling positions. Unlike some previous studies, there was little difference in terms of mean gambling hours per month or minutes per session. Some self-excluders (N = 306) can be tracked from the date their account was created through their self-exclusion history, indicating a large number of very quick self-exclusions (e.g., 25 % within a day) and a small set of serial self-excluders. Younger and older males are likely to self-exclude faster than middle-aged males (N = 242), but there is no such age pattern across female self-excluders (N = 63).