Aim To explore sleep patterns in indigenous Australian children and assess the role of sleep timing in longitudinal changes in body mass index (BMI).

Methods Latent profile analysis was conducted with the Australian Longitudinal Study of Indigenous Children (LSIC) cohort data (wave 5), to determine distinct patterns of bed and wake timing, taking account of weekday sleep duration, weekday and weekend bedtimes, and weekday wake times. Multilevel models with a random intercept were used to investigate the role of baseline sleep pattern in predicting longitudinal changes in BMI.

Results Baseline data for 1258 children (50.7% males), mean age 6.32 ± 1.52 years, indicated the presence of five classes of sleep patterns: early/long sleepers (4.5%), normative sleepers (25.5%), late sleepers (49.9%), consistent late sleepers (11.1%) and early risers (9%). Late sleeping was significantly associated with longitudinal gains in BMI. Compared with early sleepers, consistent late sleepers experienced 1.03 unit gain in BMI at follow‐up (95% CI: 0.001‐2.05, P = .05).