The purpose of the study was to translate and cross-culturally adapt the 24-item Diabetes Knowledge Questionnaire (DKQ) for Indonesian patients with type 2 diabetes (T2D) and evaluate its psychometric properties. Forward-backward translation, adaptation involving 7 experts, and pretesting to develop the Indonesian version of DKQ were conducted. Psychometric analysis was carried out among T2D patients from 40 primary health care centers in Indonesia. Known-group, convergent and discriminant validity, internal consistency and test-retest reliability were assessed. Additionally, a descriptive item analysis was conducted. In total, 39 patients participated in the pretesting and 304 patients in the validation process and descriptive analysis. Of the 24 items, 2 were adjusted during the adaptation process, and 1 item was deleted because it did not adequately reflect the original item. Known-group validity was demonstrated because patients with younger ages, higher educational levels, and longer diabetes duration had significantly higher DKQ scores. Convergent validity was demonstrated by a significant positive correlation of the DKQ scores with overall treatment satisfaction. The 23-item DKQ Bahasa Indonesia showed satisfactory internal consistency (Cronbach's α = 0.73; omega total = 0.72) and good test-retest reliability (intraclass correlation coefficient = 0.87 in a sample of 27 patients). No floor and ceiling effects were found in the item analysis. The study demonstrates adequate validity and reliability of the 23-item DKQ Bahasa Indonesia for assessing diabetes knowledge in Indonesian primary care patients with T2D. This instrument can be used to identify room for improvement and develop diabetes education programs.