Previous studies that have found changes in the teaching motivations of student teachers assumed that these changes resulted from the field experience, without actually examining whether this was indeed the case. The mixed method study described in this chapter sought to cross-sectionally compare the teaching motivations of first- and fourth-year student teachers in an initial teacher education (ITE) programme, and at relating their differences in teaching motivation to the ITE programme, particularly the field experience. In this study, 319 first-year and 460 fourth-year student teachers in Hong Kong completed a teaching motivations questionnaire, and 35 and 12 from each group, respectively, then volunteered to participate in follow-up interviews. Both year groups were high in intrinsic, altruistic, and extrinsic teaching motivations (adaptive motivation) and low in teaching as a fallback career (maladaptive) motivation, although the fourth-year student teachers had lower adaptive and higher maladaptive teaching motivations compared to the first-year students. Interview data from the fourth-year student teachers clearly revealed the importance of the field experience in shaping teaching motivations. While the reality of the heavy workload and gloomy job prospects as experienced in their field experience lowered the teaching motivations of some, their negativity can be partly offset if they have high perceived teaching competence. The implications for teaching education are discussed.