Objective: To develop a valid and reliable scale for screening adult ADHD in Indonesia using the Indonesian Version of ASRS-V1.1 and report the psychometric properties through validity and reliability testing. Methods: Following the WHO protocol in translation and adaptation of instruments, the study employed forward translation, backward translation, cultural adaptation, expert panel evaluation, pre-pilot testing to subgroups, and final adjustment to make the Indonesian ASRS-V1.1. Subsequently, an online questionnaire was distributed using Google Forms, resulting in 491 final submissions. Then, 100 subjects (50 of the screened positive for ADHD group and 50 of the screened negative for ADHD group) underwent a clinical interview with two professional psychiatrists. Results: The ASRS-V1.1 ID had an exceptional internal consistency (Cronbach’s alpha = .912 and McDonald’s omega = .914. After two weeks, test-retest reliability value was .902. The instrument’s validity was secured by KMO-MSA value of .940, total item-correlation coefficients ranged between .896-.974, and Confirmatory Factor Analysis. We found an AUC of 1.000 (95% CI: 1.000–1.000) for Part A, and .958 (95% CI: .949 – .967) for the Full-18-Questions. As for the 100 interviewed subjects, Part A had an AUC of .895 (95% CI: .873 – .917) and 0.947 (95% CI: .932 – .962) for the Full-18-Questions. Conclusion: The 18-questions ASRS-V1.1 ID is a valid and reliable instrument to assess and screen for adult ADHD in the Indonesian general population. This tool may be useful for both clinical and population studies.