Abstract Study Objectives To identify sleep multi-trajectories in children from age 1 to 5.5 years and their early correlates. Methods We collected early family, maternal, and child characteristics, including children’s nighttime sleep duration (NSD) and daytime sleep duration (DSD), night waking (NW), and sleep-onset difficulties (SOD), by parental phone interviews at age 2 months and 1-, 2-, 3.5-, and 5.5 years. Group-based multi-trajectory modeling identified sleep multi-trajectory groups. Multinomial logistic regression assessed associations with early factors. Results We identified five distinct sleep multi-trajectory groups for NSD, DSD, NW, and SOD in 9273 included children. The “Good sleepers” (31.6%) and “Long sleepers” (31.0%) groups had low NW and SOD prevalence and shorter NSD but longer DSD in “Good sleepers” than in “Long sleepers.” The “Good sleepers but few SOD” group (10.3%) had long NSD and DSD but a SOD peak at age 3.5 years; the “Improving NW and SOD” group (9.6%) showed short but rapidly increasing NSD to a plateau and high but decreasing NW and SOD; the “Persistent NW and SOD” group (17.5%) had persistent high NW and SOD. Maternal depression during pregnancy and sleep habits at age 1 (e.g. parental presence or feeding to fall asleep, sleeping at least part of the night away from own bed) were common risk factors associated with the most disordered sleep multi-trajectory groups. Conclusions We identified distinct sleep multi-trajectory groups and early life-associated factors in preschoolers. Most of the factors associated with the most sleep-disordered multi-trajectory groups are likely modifiable and provide clues for early prevention interventions. Graphical Abstract