Evaluation of the degree of adherence to self-care among Spanish type 1 diabetes (T1DM) pediatric population lacks of a validated tool. PurposeTo cross-culturally adapt and determine the psychometric properties of the Spanish version of the Diabetes Management Questionnaire to assess the degree of adherence to self-care among children with T1DM. MethodsTranslation, back-translation, and patient suggestions, were considered to obtain the Spanish version (DMQ-Sp). A cross-sectional study was conducted with 323 children (aged 8–18 years) with T1DM and their parents to determine internal reliability, structural validity, and external validity. Responsiveness to change was analyzed through a prospective longitudinal study involving 102 newly diagnosed T1DM patients. Psychometrics were evaluated for the entire sample and stratified by age (8–12 and 13–18 years). ResultsA total of 323 children with T1DM [49.8% female; age 13.3 ± 2.8 years; 155 aged 8–12; glycated hemoglobin (HbA1c) value 7.7 ± 1.0%] answered the Spanish final version. The internal consistency Cronbach's alpha was 0.76 and intraclass correlation coefficient 0.84. Test-retest reliability was r = 0.84 (p < 0.001). Fit index of structural validity was >0.7. External validity correlated inversely with HbA1c (r = −0.39; p < 0.001). The DMQ-Sp score increased significantly after 6 months of receiving the full therapeutic education program (TEP) (baseline 57.07 ± 10.81 vs. 6 months 78.80 ± 10.31; p < 0.001). ConclusionThe DMQ-Sp is reliable, valid, and sensitive to change in a large sample of children (aged 8–18 years) with T1DM and their parents. Practice implicationsDMQ-Sp can be a useful tool for diabetes teams to identify adherence to different tasks and to evaluate TEPs.