Background: School-based sleep education programmes can promote the importance of sleep health and may improve adolescent sleep. To date, only limited research has examined the feasibility of integrating sleep programmes into the school curriculum. Objectives: This study evaluated the feasibility, acceptability and preliminary efficacy of the Strathclyde intervention to encourage good sleep health in teenagers (SIESTA). Methods: A total 171 students (12-15 years, 53% women) from secondary schools in Scotland participated in the study. Recruitment and retention, data collection and design procedures were assessed to establish feasibility. Qualitative feedback on acceptability was collected via focus group discussions. Outcome measures assessing insomnia symptoms, sleep hygiene, depression, anxiety and stress were completed at baseline and post-intervention to explore the preliminary effects of SIESTA. Results: All schools that were approached consented to participate, and most students completed assessments at both time points (171) with a dropout rate of 5%. Assessment measures provided sufficient data to compare baseline and post-intervention values. Training and delivery manuals ensured successful delivery of the programme. Qualitative feedback indicated SIESTA was acceptable, and students spoke favourably about the content, delivery and techniques. Students reported that SIESTA was age-appropriate, relevant and the techniques were beneficial. There were significant improvements in insomnia and stress, but no improvements were noted for sleep hygiene, depression or anxiety. Conclusion: The findings suggest that SIESTA is feasible and acceptable for delivery via the school curriculum. The results indicate that a controlled trial is required to further investigate the efficacy of SIESTA implemented in an educational context.