Psychologists and psychological research have shaped sleep and circadian science for over a century. Yet, psychology has not fully embraced sleep as a core area of inquiry, and sleep medicine has not distinctly acknowledged the foundational role psychology plays in understanding sleep and circadian rhythms. This Question Paper invites submissions exploring psychology’s profound impact on the study, measurement and intervention strategies in sleep and circadian science, as well as reciprocal influences. Manuscripts may include historiographies of key contributors, laboratory milestones, theoretical advancements and methodological innovations within a historical context. We aim to capture the full scope of sleep psychology from its origins to a vision of its future.