Teacher inquiry is the process of applying action research to educational problems of practice, carried out by educational practitioners. The value of teacher inquiry--and all applications of action research--is that the research is being conducted by insiders, those who work directly with the problem being studied. It is based upon critical reflection and investigation into one's own professional practice. This paper presents discussion of teacher inquiry as a viable approach to resolving practitioner-based problems of practice in a process that also affords teachers the operation to generate their own knowledge about classroom practices. The process of conducting action research, along with its applications and benefits, are reviewed and contextualized within the work of classroom teachers. Perspectives held by educators regarding teacher inquiry are also discussed. The paper closes with a discussion of ways in which teacher inquiry can be highly beneficial as a means of professional growth during and following the COVID-19 global pandemic and includes a concrete example of teacher inquiry during the pandemic.