This study aims to test the efficacy of cognitive behavioural therapy for insomnia (CBTI) in conjunction with bright light therapy (BLT) in reducing insomnia symptoms in adolescents with insomnia and delayed sleep phase (also known as evening chronotype or “night owl”). This study also examines the effects of CBTI and BLT on the measures of quality of life, daytime-related symptoms, and functioning (e.g. sleepiness, fatigue) as well as subjective and objective sleep measures.