Wait time, or the pauses between questions and responses, has been demonstrated to be an important factor influencing classroom learning. This paper reviews the key variables that have emerged in wait time research over the past 20 years. Progress in defining and measuring wait time has resulted in improved methodology for wait time research. Teacher training procedures have been improved through the use of several techniques, including modeling, pause feedback teaching aids, and strategies for modification of traditional classroom recitations, which lead to inquiry-based guided discussions and interactional dialogue patterns. Further research is needed to measure the effects of pauses and interaction patterns on affective transactions in the classroom. Research linking wait time variables with achievement outcomes is also needed. (GDC)