Background <p>Adolescents’ participation in daily activities is linked to positive effects, including improved academic performance, reduced school dropout and delinquency rates, increased social engagement, and influences well-being. Conversely, limited participation is associated with negative consequences, such as limited learning, behavioural problems, lower self-esteem and higher rates of substance use, emotional difficulties. Despite this, there is a lack of a comprehensive tools designed specifically for adolescents, which encompass both objective and subjective dimensions of participation across contexts.</p> Aim <p>To report on the development and initial psychometric properties of the Adolescents Participation Questionnaire (APQ).</p> Methods <p>Three hundred and seventy-nine typically achieving students and 103 underachieving students filled-out the APQ. Two expert panels evaluated its content validity by using questionnaires and a specification table.</p> Results <p>I-CVI and S-CVI were acceptable to excellent. The multi-rater linear weighted kappa statistic was good to excellent. Reliability estimation was acceptable for the entire questionnaire and for each context separately (<i>α</i> = 0.61–0.75). Test-retest reliability for each scale and context separately demonstrated medium to excellent reliability (ICC = 0.42–0.92). Construct validity was established by significant differences found between two known groups.</p> Conclusions/significance <p>The APQ is a suitable tool for assessing adolescents’ participation. Further studies are necessary to expand the established psychometric properties.</p>