Introduction <p>Gestational diabetes mellitus (GDM) is the most common medical complication in pregnancy. Its onset puts a heavy strain on the positive connotation of pregnancy and is accompanied by feelings of fear, uncertainty, stress, a sense of losing control, a poorer perception of health and a reduced quality of life (QoL). QoL has a significant impact on the success of therapy because of its link to adherence and clinical outcomes. Therefore, its measurement has been suggested to be implemented as a clinical standard in GDM care. Since the Persian GDMQ-36 is the only GDM-specific questionnaire so far, the aim of our study was to develop a disease-specific QoL questionnaire in German.</p> Methods <p>After translating the GDMQ36, we assessed the comprehensibility as well as face and content validity by an expert rating (<i>n</i> = 20) and conducted two pre-tests, including cognitive debriefings and structured interviews with women suffering from GDM (<i>n</i> = 30, <i>n</i> = 12).</p> Results <p>The translated questionnaire had to be adapted and revised due to linguistic and cultural comprehension difficulties. Based on the findings of our qualitative studies, 33 questions about missing aspects were added, while most existing phrases needed to be modified or some even excluded. The preliminary version of the questionnaire contains 69 items within three domains (physical, psychological, social) and is subdivided into six facets (medical, treatment associated, emotional, behavioral, motivational, and social aspects).</p> Conclusion <p>The questionnaire has the potential to provide a more comprehensive overview of women’s expectations, needs, impairments, and problems related to illness and treatment. It is planned, to prospectively test the newly developed GDM-QOL questionnaire to evaluate its psychometric performance in terms of validity and reliability.</p>