Insufficient self-regulation and reduced awareness of self-regulatory skills have been discussed as possible explanations for academic difficulties. However, instruments for assessing metacognitive knowledge of self-regulation in young school children have been lacking so far and it has been questioned whether younger school children are able to make accurate self-judgments on their regulatory skills. We present a new age-appropriate self-rating scale for the assessment of self-regulatory skills in young school children--the Self-rating of Self-regulatory Function (SelfReg)--which was validated on a representative sample of 107 school children aged 8 to 10 years. Confirmatory factor analysis of the scale offered evidence for a one-dimensional rather than a multidimensional model. In a second step, self-ratings on the SelfReg of 21 children with impaired self-regulatory skills and various types of behavioural, developmental, or academic difficulties were compared to self-ratings of 21 normal controls. Children with dysfunctional self-regulation rated themselves as significantly more impaired on the SelfReg than control children. Analyses of discrepancies between parents' and/or teachers' ratings and self-ratings of the children did not discriminate between the two groups, indicating that self-ratings in children with dysfunctional self-regulation and control children, though significantly different, were equally accurate. It is concluded that children as young as 8 to 10 years are able to make differential and accurate judgments on their self-regulatory skills when assessed with an age-appropriate instrument. (Contains 6 tables and 2 figures.)