In recent years, preschooler's self-regulation has been extensively researched. This systematic review deals with the overlaps and differences among the many different terminologies and definitions of self-regulation in childhood and the association with preschooler's social-emotional and behavioural development. A systematic literature search in bibliographic databases identified 22 studies, published between 2011 and 2017, which met further inclusion criteria. Our review revealed considerable similarities and differences regarding definitions, core components, and measurements of self-regulation. Results regarding preschooler's social-emotional and behavioural outcomes were heterogeneous, but overall the significance of children's level of self-regulation was emphasized. In order to make clear statements about the impact on children's development, self-regulation must be defined uniformly. This study indicates the need for an integrative model for self-regulation in childhood, considering dimensionality, individual components, and its organization.