Efforts to improve the quality of education have been endeavored by various means ranging from procurement of facilities and infrastructure, curriculum, procurement of resource books, improvement of evaluation systems, improvement of the quality of human resources, one of which is improving teacher competence at all levels of education, to make teachers who professional. Based on the background of the problem above, the authors conducted a study with the aim of: (a) To explain the work of SMK Manbaul Ulum teachers (b) To analyze the efforts of school principals in increasing work motivation in developing the professionalism of SMK Manbaul Ulum teachers. (c) To analyze the obstacles and solutions made by the School Principal to improve work motivation in developing the professionalism of vocational school teachers Manbaul Ulum. The method used in this study is a qualitative approach that intends to understand the phenomena about what is experienced by research subjects such as: perception, action , and others, holistically. Data collection is done by observation, documentation, and interview techniques. Data analysis techniques include data reduction, data presentation, and drawing conclusions. The conclusion of this research is that: teacher training requires a long time to achieve a significant change in results, therefore the success or failure of teacher professional development must be measured from the performance concerned and not from additional knowledge and or skills alone.