In order to become proficient native speakers, children have to learn the grammatical rules of their language. These grammatical rules can define morpho-syntactic relations between neighboring as well as distant elements of a sentence, so-called non-adjacent dependencies (NADs). Previous neurophysiological research suggests that NAD learning comprises different developmental stages during early childhood. Children up to 2 years of age show evidence of associative NAD learning under passive listening conditions, while children starting around the age of 3 to 4 years fail to show learning under passive listening, similarly to the pattern observed in adults. To test whether the transition between these developmental stages occurs in a gradual manner, we tested young children’s NADlearning in a foreign language using event-related potentials (ERPs). We found ERP evidence of NAD learning across the age of 1 to 3 years. However, the amplitude of the ERP effect indexing NAD learning decreased linearly with increasing age. These findings indicatea gradual transition in children’s ability to learn NADs associatively under passive listening during early childhood. Cognitively, this transition might be driven by children’s increasing morpho-syntactic knowledge in their native language, hindering NAD learning in novel linguistic contexts during passive listening. Neuroanatomically, changes in brain structure might play a crucial role, especially the maturation of the prefrontal cortex, which promotes top-down learning, as opposed to bottom-up, associative learning. In sum, our study provides evidence that NAD learning under passive listening conditions undergoes a gradual transition between different developmental stages during early childhood.Research HighlightsTransition between different developmental stages of non-adjacent dependency learning during early childhood evidenced by event-related brain potentialsChildren between 1 and 3 years of age showed learning of non-adjacent dependencies in a foreign language during passive listeningBrain responses revealed associative non-adjacent dependency learning across the tested age range, triggered by passive listeningGradual decrease of the strength of associative non-adjacent dependency learning, during early childhood