In many mentally ill children, a new phenotype of affective and behavioural dysregulation can be observed. Not much is known about development and maintenance of this phenotype. A possible risk factor that has been suggested is disturbed sleep. The co-occurrence of sleep disturbances and psychiatric symptoms is significant and it has been postulated that there are specific patterns of sleep disturbances for different psychiatric symptoms. The aim of this study, therefore, is to investigate the specific relation of sleep disturbances and affective dysregulation in school children and whether a specific pattern of sleep disturbances is associated with or of predictive value for affective dysfunctions. 4,774 school children took part in the Cologne Sleep Study and emotional disturbances and sleep abnormalities were assessed by parent reports. Of the sample, 206 children were identified as showing signs of severe affective and behavioural dysregulation (DP), 276 children were reported as showing a subclinical form (SUB-DP). Both groups reported significantly more sleep disturbances than healthy controls with moderate to large effect sizes. Differences between SUB-DP and DP exist, however, were not of clinical relevance (d < 0.03). Particularly, emotional problems were associated with sleep disturbances with small to moderate correlation coefficients. The regression analysis revealed a small, but significant influence of impaired daytime behaviour on affective dysregulation with 16.1 % of variance being explained. No specific patterns of sleep disturbances could be identified. However, impaired sleep and daytime behaviour in both the SUB-DP and DP group are indicated. Consequently, practitioners should address sleep problems in children with affective dysregulation.