Student performance in general subjects such as language and mathematical skills is poor in secondary vocational education. A professional culture of teaching-including recruitment of well qualified teachers, effective teacher collaboration and effective teaching practice-could be the key to success. To what extent is there a professional culture of teaching in vocational education? Do differences in the professional culture of teaching affect student achievement? National achievement tests on functional language skills, mathematical skills and information processing were administered to third grade students (N = 3,381) in 116 secondary schools offering vocational education across Flanders. Their teachers (N = 184) completed an online questionnaire about their collaboration and teaching practice. We found evidence that teacher collaboration and effective teaching practices are strongly correlated. Positive correlations were found between combinations of characteristics of a professional culture of teaching and student achievement. However, in many schools a professional culture of teaching is not yet a reality. Our findings demonstrate a need for continually providing support within a professional culture of teaching to prevent teachers from leaving. Improving professional growth for teachers and their teaching teams is also needed, as well as a shift in education policies to support these needs.