This study intended to examine The Effectiveness of Guidance and Counseling Practices on Students' Career Development in Secondary Schools in Temeke Municipality using embedded research design. It was undertaken in Temeke Municipality, Dar es Salaam Region, Tanzania. The target population was heads of secondary schools, teachers, students, and ward educational officers. The sample size used comprised of 15 teachers, equivalent to 10% of the 150 teachers in the selected secondary schools, three school heads, and 120 students as 10% of 1,200 students from Forms III and IV. Probability and non-probability sampling tactics were employed in the selection of respondents from the targeted population. Observation method, documentary review, interview guide and questionnaires were used to collect primary data while secondary data were obtained in the documents. Data were analyzed both quantitatively and qualitatively. The findings reveal the existing lack of specialized personnel in the field of career guidance and counseling. Instead, teachers are randomly picked to hold that position; a teacher seen to be morally upright and religious is appointed and tries to do the best possible to support these students. Through the study, there was glaring evidence that the tight school timetable does not give room for students to consult their teachers -particularly the time table for extra-curricular activities. It has been established, according to the survey, that guidance and counseling practices face limited teaching and learning materials, counseling offices, negative perception from students and limited support from the government. The findings also show that students experience little support from parents and teachers. Schools in the sample lacked special counseling rooms and even confidentiality from teachers. It is, thus, recommended that special in-service training and seminars should be provided to teachers expected to be school guidance-counselor and there should be financial support from parents, government and the community at large.