Sleep tracking has become a growing area of self-tracking, yet the breadth of users’ interactions with sleep-tracking technology has not been comprehensively synthesised. To address this gap, this study analyzes 51 empirical research articles following a three-phase literature review process. Guided by a human–computer interaction framework, we organised the extant research into five components: (1) user, (2) sleep-tracking technology, (3) use context along with corresponding tasks, (4) use and impact (user-oriented outcomes) and (5) design insight (technology-oriented outcomes). The first three components represent the antecedents of sleep tracking, while the latter two capture its outcomes. Based on these insights, we present a synthesising framework to elucidate current research concerning users’ interactions with sleep tracking technology. Drawing upon our findings, we propose two future research agendas for research design: (1) balancing qualitative with quantitative methods and (2) strengthening theoretical foundations. For future research topics, we put forward four agendas: (1) respect for individual differences and their impact on sleep tracking, (2) sleep-tracking technology evolution, user-centered design and its compatibility, (3) the role of stakeholders and external environment and (4) impacts beyond benefits: underlying mechanisms of use, effective use, behavioural change and potential side effects.