Background This rapid review examines changes in the mental health of the German child and adolescent population during the COVID-19 pandemic. Methods The basis are 39 publications, which were identified by means of systematic literature search (until 19.11.2021) and manual search. The databases of the included publications were systematized with regard to their representativeness for the general population, and the indicators used were categorized with regard to the depicted constructs and their reliability. Results The large majority of the studies took place at the beginning of the pandemic until the summer plateau 2020. Representative studies mainly reported high levels of pandemic-related stress, increases in mental health problems, and negative impacts on the quality of life. Non-representative studies showed mixed results. Vulnerable groups could only be identified to a limited extent. Both routine and care-related data showed declines in the outpatient and inpatient service utilisation during the various waves of the pandemic followed by catch-up effects. Children and adolescents turned out to be more vulnerable during the pandemic compared to adults, but their stress levels varied with the waves of the pandemic and the related containment measures. Conclusions A future forward-looking crisis and pandemic management requires a close-knit and continuous surveillance of the mental health of children as well as an improved identification of risk groups.