This study is specifically aimed at evaluating commercially available metal oxide (MOx) sensors for real-time monitoring of volatile organic compounds (VOCs) in typical indoor environments. To evaluate MOx sensors’ performance, we used a 50 L environmental chamber system to provide a well-controlled testing environment. The VOC types and test concentrations were based on relevant indoor air quality (IAQ) standards and guides in the literature. Test VOCs included toluene, formaldehyde, m-Xylene, phenol, benzene, naphthalene, acetaldehyde, acetone, dichloromethane, tetrachloroethylene, 1,1,1-trichloroethane. The evaluation tests are categorized into individual VOC tests, mixture VOCs tests, temperature and relative humidity dependence tests, short-term stability tests, and long-term drifting tests to investigate the sensitivity to specific VOC, mixture co-influence under realistic condition, moisture compensation, and reliability. This paper focuses on the procedures and results of the toluene test, identifying necessary improvements in the algorithm through comparisons between raw signals and TVOC readings. Results of this study will help provide guidance on the selection and utilization of MOx VOC sensors for VOC monitoring and IAQ control.