Objectives: To evaluate the validity and reliability of the Thai version of the job content questionnaire (TJCQ) both 22-item and 45-item versions. Materials and Methods: The study encompassed 10,450 employees in Songkhla province, Thailand. A 45-item job content questionnaire (JCQ) was translated and back translated complying with the JCQ usage policy. TJCQ covers seven scales as follows: psychological demand, decision latitude, supervisor support, coworker support, physical demand, job security and hazard at work. Internal consistency was examined using Cronbach's alpha coeffi cient. Factor validation was tested using both exploratory and confi rmatory factor analysis. Results: Both 22-item and 45-item versions of TJCQ demonstrated acceptable internal consistency in nearly all scales except for psychological demand. The exploratory and confi rmatory factor analysis result gave support to 5-factor model in 22-item version and 8-factor model in 45-item version of TJCQ. The psychological demand scale tended to split into two subscales. Other scales were consistent with the expected dimensions though some items extracted differently along the theoretical dimensions. Conclusions: Our study provided evidence for the reliability and validity of the TJCQ among Thai employees and supported the ongoing debate on multifaceted psychological demand and its complexity, making it feasible to extend the TJCQ beyond its original structur.