ObjectiveThe aim was to study, with a developmental approach, the longitudinal association between night-waking from age 2 to 5–6 years and behavior at age 5–6 years. MethodsWithin the French birth cohort study Etude sur les Déterminants pré et post natals du développement et de la santé de l'ENfant (EDEN), repeated measures of children's night-waking were collected at age 2, 3 and 5–6 through parental questionnaires and were used to model night-waking trajectories. Behavior was assessed with the “Strengths and Difficulties Questionnaire,” which provides five subscales measuring a child's conduct problems, emotional symptoms, peer relation problems, antisocial behavior, and hyperactivity/attention problems. The behavioral subscales were dichotomized at the tenth percentile. Multivariable logistic regressions, adjusted for parents' socio-economic factors, parental characteristics, and children's characteristics and sleep habits allowed us to study, in 1143 children, the association between night-waking trajectories from 2 to 5–6 years and behavior at age 5–6 years. ResultsThe “2 to 5–6 rare night-waking” trajectory represented 78% of the included population (n = 896), and the “2 to 5–6 common night-waking” 22% (n = 247%). Children belonging to the “2 to 5–6 common night-waking trajectory” had, at age 5–6, increased risk of presenting emotional symptoms (odds ratio [OR] = 2.17, 95% CI = 1.27–3.70, p = 0.004), conduct problems (OR = 1.63, 95% CI = 1.00–2.65, p = 0.050), and hyperactivity/attention problems (OR = 1.61, 95% CI = 1.00–2.57, p = 0.049). After adjusting for baseline behavior at age two years, only the association with emotional symptoms remained significant (OR = 2.02, 95% CI = 1.15–3.55, p = 0.015). Results did not differ according to sex. ConclusionResults suggest that the persistence of night-waking difficulties in early years is positively associated with emotional symptoms, hyperactivity/inattention, and conduct problems.