This article has two purposes: (1) to investigate how Taiwanese teachers of English as a Foreign Language turned experiences into critical reflections via journal writings and (2) to describe how they gauged critical reflections as teaching inquiry. The results indicate that critical reflection as teaching inquiry helped the teachers deal with situations of uncertainty, instability, and value conflict in multiple contexts. Critical reflections enhanced teachers' understanding and brought about changes in their awareness of instructional effectiveness and teaching beliefs in their practice.