This study aims at investigating effects of planning for supervision and its impact on the professional development of student teachers in Higher Technical Teacher Training Colleges in Cameroon. It is based on the problem of inadequate clinical supervision model of planning which has negative impacts on the professional development of student teachers. The main objective was to ascertain how clinical supervision influences professional development of student teachers in higher technical training colleges in Cameroon. Based on this, research questions were formed and hypotheses generated. The scope was limited to student–teachers and supervisors in Higher Technical Teacher Training Colleges in Cameroon. The sample population was 346 student teachers and 08 supervisors. The Elizabeth Holloway’s System model (1995), was used as theoretical backup of the study. The study made use of the sequential explanatory design and used the purposive sampling for selecting the schools and the classes for the study. It also made use of the inferential and descriptive statistics. The instruments for data collection were the questionnaire for student–teachers, interview for the supervisors and cooperating teachers and observation guides. The questionnaires were made up of items about planning for supervision. The supervisors were equally interviewed on this. From the results we have the following conclusions: 81.1% of supervisors do not carry out planning for supervision with their supervisees. This means that there is a significant impact on planning for supervision on the professional development of student teachers in Higher Technical Teacher Training Colleges in Cameroon. The study recommends that supervision schools be opened to train supervisors.