Health literacy is a promising approach to promoting health and preventing disease among children and adolescents. Promoting health literacy in early stages of life could contribute to reducing health inequalities. However, it is difficult to identify concrete needs for action as there are few age-adjusted measures to assess generic health literacy in young people. Our aim was to develop a multidimensional measure of health literacy in German to assess generic health literacy among 14- to 17-year-old adolescents, namely, the “Measurement of Health Literacy Among Adolescents Questionnaire” (MOHLAA-Q). The development process included two stages. Stage 1 comprised the development and validation using a literature review, two rounds of cognitive interviews, two focus groups and two rounds of expert assessments by health literacy experts. Stage 2 included a standard pretest (n = 625) of the questionnaire draft to examine the psychometric properties, reliability and different validity aspects. The MOHLAA-Q consists of 29 items in four scales: (A) “Dealing with health-related information (HLS-EU-Q12-adolescents-DE)”; (B) “Communication and interaction skills”, (C) “Attitudes toward one’s own health and health information”, and (D) “Health-related knowledge”. The confirmatory factor analysis indicated a multidimensional structure of the MOHLAA-Q. The internal consistency coefficients (Cronbach’s α) of the scales varied from 0.54 to 0.77. The development of the MOHLAA-Q constitutes a significant step towards the comprehensive measurement of adolescents’ health literacy. However, further research is necessary to re-examine its structural validity and to improve the internal consistency of two scales.