This study examines the early emergence of sensory reactivity and novelty awareness and their relations to children's behaviours with peers. A total of 260 parents (242 mothers, 18 fathers) and 10 teachers of 260 children (131 male, 129 female; M?=?63?months; SD?=?8.80; range?=?39-81) participated. Structural equation models indicate that sensory reactive children appear to be less social (i.e. prosocial and friendly), more likely to engage in solitary-active play behaviour, and more prone to utilize instrumental aggression in peer interactions. Children scoring high on novelty awareness tend to be more social (i.e. prosocial, friendly, and control impulses), better able to appropriately and punctually comply with tasks given by teacher, less likely to engage in a number of solitary play behaviours (i.e. solitary passive and solitary active), less likely to utilize instrumental or reactive aggressive strategies, and more likely to dodge negative peer interactions by avoiding bullies. Furthermore, the associations between sensory reactivity/novelty awareness and children's behaviours differ from those of other dimensions of temperament (i.e. activity level and emotionality). This suggests that novelty awareness and sensory reactivity uniquely contribute to our overall understanding of children's temperament and its correlates.