Background: Anxiety impairs adolescent development and is a risk factor for psychopathology. However, factors related to anxiety impairment's severity remain poorly studied. Objective: This study aims to document anxiety impairment across different domains in adolescents and to study associated factors (sociodemographic, specific anxiety, and depressive symptoms, psychological vulnerabilities). Methods: Adolescents aged 11 to 17 (N = 4616) participated in this cross-sectional correlational study. They were recruited from several schools in Canada and answered questionnaires. Results: Anxiety impairment was higher in the school domain, compared to the social and family domains. Respectively, 9.64%, 5.23% and 2.02% of adolescents reported experiencing moderate or high impairment in these domains. Controlling for symptom severity, anxiety impairment seemed higher in females, adolescents from regular programs and those starting high school. All types of symptoms predicted school impairment, except the obsessive-compulsive (OC) ones. Symptoms of panic, generalized anxiety, post-traumatic stress (PTS), as well as depressive symptoms were moderately related to impairment, while the other symptoms were weakly related. Only OC and PTS symptoms did not predict impairment in the social domain, and only PTS, separation anxiety and depressive symptoms predicted impairment in the family domain. Perfectionism, intolerance of uncertainty and negative problem orientation predicted impairment levels after controlling for symptom severity. Conclusions: This study notes relatively high rates of anxiety impairment in high school and suggests more school impairment. It offers possible explanatory factors that could be useful to establish more detailed models and interventions.