The objective of the study is to explore the univariate and multivariate differences in behavioural problems among children with disorders in expressive or mixed receptive–expressive language development and children with unimpaired language development. 94 children with language development disorders (LDD) between the ages of 4 and 6 years and 94 children (matched by age and sex) without disorders of language development were compared concerning behavioural problems, as measured by the German version of the Child Behavior Checklist/4-18. Results: 32 children (34%) with LDD showed behavioural problems in the clinical range, whereas only 6 control subjects (6%) had scores in this range. Univariate group comparisons between patients and control subjects showed significant differences in all 8 syndromes and the scale “other problems,” with patients having higher scores. Multivariate stepwise discriminant analysis showed a significant discriminant function by the scales “other problems,” “social problems,” “anxious–depressed,” “thought problems,” “attention problems,” and “delinquent problems.”