Most practitioners teaching English to speakers of other languages (TESOL) will agree that students come with some expectations about course content and teaching methodology and that these expectations play a vital role in student motivation and learning. However, the study of student expectations has been a surprising omission from Second Language Acquisition research. In the studies reported here, we develop a model of student expectations by adapting the Expectation Disconfirmation paradigm, widely used in consumer psychology. Student and teacher perspectives on student expectations were gathered by interviews. Responses shed light on the nature of expectations, factors causing expectations and effects of expectation fulfilment (or lack of it). The findings provide new avenues for research on affective factors as well as clarify some ambiguities in motivational research in second language acquisition. The model presented here can be used by teachers or institutions to conduct classroom-based research, thus optimising students' learning and performance, and enhancing student morale. (Contains 4 tables, 2 figures and 3 endnotes.)