Stigma has been identified as a barrier to help-seeking for mental health problems. The aim of the current study was to examine levels of personal and perceived generalized anxiety disorder stigma among an adolescent population, and to identify potential predictors of these constructs. A total of 1,840 adolescents (64.6% female) aged between 12 and 18 years participated in the current study. As a part of the preintervention questionnaire of the Y-Worri Project, participants completed the Generalized Anxiety Disorder Stigma Scale (GASS) and a number of sociodemographic and symptom outcome measures. Participants reported significantly higher levels of perceived stigma than personal stigma. Higher personal generalized anxiety disorder stigma was associated with being male, having a non-English speaking background, not living with 1 or both parents, and having lower anxiety literacy scores. Higher perceived generalized anxiety disorder stigma was associated with being male, living with 1 parent and having higher levels of depressive symptoms and anxiety literacy. Stigmatizing attitudes toward generalized anxiety are common among adolescents. Based on the predictors of personal and perceived stigma identified in the current study, it may be particularly beneficial to target antistigma interventions to males, those from culturally diverse backgrounds, and those who have had limited exposure to generalized anxiety.