This article introduces the Job Content Questionnaire (JCQ) as a tool for assessing psychosocial job characteristics. Part I describes the development and theoretical basis of the JCQ scales, which measure job demands, decision latitude, social support, physical demands, and job insecurity. These scales assess the job strain model and its predictions about stress risk and behavioral responses under conditions of high psychological demands and low decision control. Part II reports on the cross-national validity of the JCQ scales based on studies of over 10,000 men and 6,000 women across multiple countries. Part III reviews comparisons of intercountry and interoccupation differences in JCQ scale scores.