In this study, issues of validity and reliability of a wide range of instruments used to measure technological pedagogical content knowledge level of English teachers were discussed. To this end, the search in the databases of ERIC, ScienceDirect, Scopus, EBSCOhost, and Web of Science was conducted. As a result of applying a set of criteria to publications retrieved from the databases, 60 studies (including 40 articles, 14 dissertations and 6 conference papers) were found suitable for analysis in the current study. A two-level analysis was conducted. First one was study-level analysis focusing on general characteristics of each study and the second one was an instrument-level analysis that focuses on target audience and research instruments. As a consequence of the analysis at the study-level, 128 instruments were classified into five types of instruments including, open-ended questionnaire, observation, performance assessment, interview, and self-report instruments. At the instrument-level analysis, issues of validity and reliability of those instruments and target audience were investigated. The findings revealed that 60% of the reviewed studies did not provide any index of reliability, and similarly over 80% of the studies presented no evidence of validity.