External suspension (fixed period exclusion) from school is a common disciplinary response to students who display disruptive behaviours and do not adhere to school rules. Few studies have compared suspended and never suspended students' perceptions of risk and protective factors in the family, school, and peer domains, as well as measures of problem behaviours and emotional problems in the one study. Three hundred and four adolescents from five schools in southern Australia completed a self-report questionnaire that asked about behavioural and mental health problems, and risk and protective factors. Seventy-four (24%) of the participants had been previously suspended from school at least once. Having been previously suspended was associated with self-report of a greater level of problem behaviours and emotions, poor family management, low school commitment, diminished teacher relationships, and interactions with antisocial peers. School suspension appears likely to be applied to students that lack the ability to self-regulate their behaviours and emotional problems in the classroom. By excluding students from school, pre-existing behavioural problems may be exacerbated by diminishing school protective factors and increasing exposure to known risk factors. Adolescents most at risk of being suspended would benefit from alternative school behaviour management policies and procedures that maintain the school environment as a protective factor.