The study explored secondary school mathematics and science teachers’ views on training and professional development in Namibia. Quantitative approach was employed to gather information on professional development and relevance of teacher training to identify among others’ problems and challenges mathematics and science teachers at the secondary level in Namibia face every day in schools and their classrooms. The target population was mathematics and science secondary school teachers in the two regions, that is, Ohangwena and Omusati regions out of 14 regions. The study sample size was 54 respondents. Data were collected through an online questionnaire and analyzed using descriptive statistics. The study findings show that workshops or training sessions are the predominant form of professional development, and major problems and challenges mathematics and science teachers face every day are inadequate mentoring programs and teaching materials, large class sizes, insufficient professional development opportunities, and limited access to technology. The latter two make it harder for teachers to adapt to the evolving needs of their students and the changing demands of the twenty-first-century science, technology, engineering, and mathematics workforce. A small number of participants noted leadership style as one of the challenges influencing teacher quality. Educational policies are not strongly supportive of mathematics and science teachers in terms of teacher empowerment and student relationship building. There is, therefore, a need to further examine whether these professional development opportunities are equitably accessible to teachers across different socioeconomic backgrounds, geographic regions, and school settings to promote fairness and excellence in the education system.