The Subjective Happiness Scale (SHS) has been widely used to measure global happiness. However, only a few studies have critically evaluated the psychometric properties of the Indonesian version of the SHS using rigorous techniques. This study aimed to address this gap by conducting a comprehensive assessment of the SHS using complementary Classical Test Theory (CTT) and Item Response Theory (IRT) frameworks to provide a robust and nuanced evaluation of the scale’s reliability, validity, and item-level performance. Indonesian-speaking participants completed the Indonesian SHS, the General Health Questionnaire-12 (GHQ-12), and the Satisfaction with Life Scale (SWLS). Results indicated that the Indonesian SHS demonstrated acceptable reliability and validity. Nevertheless, Item 4 consistently underperformed in capturing the happiness construct. These findings highlight the importance of cultural and linguistic adaptation when using the SHS in diverse cultural contexts. The study offers robust psychometric evidence of the scale’s internal structure, item functioning, and construct validity of the Indonesian SHS, supporting its use in future well-being research. © Universiti Putra Malaysia Press