During COVID-19, Australian adolescents have experienced worsening psychological wellbeing and are spending an extra four hours daily socialising online. State authenticity (SA; being the real me, right now) positively influences psychological wellbeing. However, little is known about adolescent SA, especially when actively socialising online. This exploratory mixed-methods research aims to develop a ground-up conceptual framework and measure of adolescent SA in dynamic online social interactions (AdSA-O). It involves identifying potential aspects belonging to adolescent SA from interviews exploring their understandings and experiences in dynamic online settings (e.g., Zoom, Discord); creating and validating an AdSA-O self-report scale; then exploring connections between AdSA-O, autonomy, and psychological wellbeing. This foundation will illuminate avenues toward enhancing or maximising AdSA-O, ultimately strengthening positive psychological outcomes.