Background . Multimorbidity is a growing problem. The number and complexity of (non-)pharmaceutical treatments creates a great burden for patients. Treatment burden refers to the perception of the weight of these treatments, and is associated with multimorbidity. Measurement of treatment burden is of great value for optimizing treatment and health-related outcomes. Objective. We aim to translate and validate the Multimorbidity Treatment Burden Questionnaire (MTBQ) for use in the Dutch population with multimorbidity and explore the level of treatment burden. Methods. Translating the MTBQ into Dutch included forward-backward translation, piloting and cognitive interviewing (n=8). Psychometric properties of the questionnaire were assessed in a cross-sectional study of patients with multimorbidity recruited from a panel in the Netherlands (n=959). We examined item properties, dimensionality, internal consistency reliability and construct validity. The level of treatment burden in the population was assessed. Results. The mean age among 959 participants with multimorbidity was 69.9 (17–96) years. Median global NL-MTBQ score was 3.85 (IQR 0-9.62), representing low treatment burden. Significant floor effects were found for all 13 items of the instrument. Factor analysis supported a single-factor structure. The NL-MTBQ had high internal consistency (α=0.845), and provided good evidence on the construct validity of the scale. Conclusion. The Dutch version of the 13-item MTBQ is a single-structured, valid and compact patient-reported outcome measure to assess treatment burden in primary care patients with multimorbidity. It could identify patients experiencing high treatment burden, with great potential to enhance shared-decision making and offer additional support.