For the first time in the Netherlands, the Adjustment Scales for Early Transition in Schooling (ASETS) have been applied to kindergarten and first-grade elementary school. A study was conducted to examine the relation between the different behavioral (phenotypes) and situational dimensions (situtypes) of the ASETS and learning performance on standardized language and numeracy tests. Results show that a proportion of children experience socioemotional and behavioral problems. Among boys, in particular, emotional or behavioral problems are significant. Furthermore, results show that these problems translate into a fairly consistent pattern of negative correlations with language and numeracy performance. These outcomes support the assertion that some children are not yet ready for school. It therefore seems important that the structured academic approach that is central to many methods used in early childhood education undergoes critical reflection, as by no means all target group children are ready for this approach.