The national 'Competence for Quality' in-service programme in Norway aims to enhance the subject knowledge and instructional competences of primary and secondary school teachers across subjects. The programme is evaluated annually through a teacher survey which, however, does not capture in depth how the programme impacts on participants. This study tracked four primary school teachers of English over 26 months and found that the in-service course they completed had positive effects on their confidence to speak English in class and their oral fluency, though a reduction in the accuracy of their classroom English was also noted. Variable but positive changes in teachers' classroom practices during the course were noted too. Overall, the study highlights links between teacher knowledge, teacher confidence and teacher change, provides insight into how professional development impacts on these dimensions of teaching, and illustrates how case studies can complement quantitative evaluations of in-service programmes for teachers.