Culture plays a role in mental health, partly by defining the characteristics that are indicative of positive adjustment. In Chinese cultures, positive family relationships are considered central to well-being. The culturally emphasized characteristic of family harmony may be an important factor associated with psychopathology. This article presents the development and psychometric examination of the Family Harmony Scale (FHS), an indigenously developed 24-item instrument tapping family harmony in 17,461 Hong Kong residents from 7,791 households. A higher-order model with 1 second-order factor and 5 first-order factors fit the data well and showed factorial invariance across sex and participants in different family roles. A 5-item short form (FHS-5) was also developed, with 1 item from each first-order factor. The short scale showed, as expected, a single-factor structure with good fit. Both scales demonstrated high internal consistency, acceptable test-retest reliability, and good convergent and discriminant validity. The 24-item FHS was negatively associated with depressive symptoms after accounting for individual risk factors and general family function. Family harmony moderated the relationship between life stress and depressive symptoms such that those individuals who reported low family harmony had stronger associations between life stress and depressive symptoms. This study adds to the literature a systematically developed, multidimensional measure of family harmony, which may be an important psychological protective factor, in a large urban Chinese sample. The FHS-5 minimizes operational and respondent burdens, making it an attractive tool for large-scale epidemiological studies with Chinese populations in urban settings, where over half of China's 1.4 billion people reside.