Giftedness is a multidimensional condition. It is increasingly put forward that gifted children (GC) could be a population at high risk for sleep problems. The current study investigated GC and typically developing children for their habitual sleep, night-to-night sleep variability, and parental reports of child sleep. The sample consisted of 62 GC (31 girls; mean age = 9.63 ± 1.71 years) and 62 typically developing children (31 girls; mean age = 9.68 ± 1.68 years). Groups were age and sex matched. Giftedness was identified using Renzulli's 3-factor definition of giftedness. Sleep duration, quality, and night-to-night variability were assessed using actigraphy. Parents were asked to complete the short-form version of the Children's Sleep Habits Questionnaire to report on their child's sleep. Groups were compared with independent sample t-tests and chi-square analyses. GC displayed lower sleep efficiencies, more wake time after sleep onset, and more night-to-night sleep variability than typically developing children. GC were found to experience less social jetlag compared to typically developing children, and they also showed more clinically significant sleep problems as reported by parents. Sleep maintenance and stability tend to be challenged in GC. While there is growing evidence that greater sleep variability is associated with poorer physical and emotional health, studies have yet to examine these associations in GC specifically to get a better understanding of giftedness. Overall, there is a need for research focused on both predictors and consequences of sleep patterns and sleep variability in GC. Bastien L, Théoret R, Bernier A, Godbout R. Habitual sleep and intraindividual variability of sleep in gifted children: an actigraphy study. J Clin Sleep Med. 2023;19(5):925-934.