Data on mental health care use of children and adolescents in Germany is scarce. This study investigates the degree of mental health care use, its trajectories and influencing factors among children and adolescents in Germany, using longitudinal data of the BELLA study. The BELLA study is the mental health module of the representative German National Health Interview and Examination Survey for children and adolescents (KiGGS). Baseline data of N = 2,863 participants aged 7–17 years were collected between 2003 and 2006. The study sample was followed up in three additional measurement points, assessing general mental health problems and impairment, specific mental health problems, and mental health care use. In the current study, we analysed data from the first three measurement points. At baseline, 5.9 % of all participants used mental health care in the past 12 months. Among those with general mental health problems, 29.5 % sought professional help. Only a minority of participants reporting mental health care use at baseline also sought help at the following two measurement points. Analysing a random intercept only model, mental health care use was found to be more likely among participants living in larger communities as well as in the Eastern part of Germany, among those participants with impairment of mental health problems, and signs of externalizing problems. Our results indicate a temporary character of mental health care use. Participants’ impairment was identified to be the strongest predictor of mental health care use.