The study investigated the trend of performance of students in selected Science, Technology, Engineering, and Mathematics (STEM) subjects in the Basic Education Certificate Examination (BECE) conducted by Ogun State Ministry of Education, Science and Technology, Nigeria. The study adopted an ex post facto research design to carry out the trend analysis of students' results in the examination from 2011 to 2015. All the students that enrolled and sat for the BECE examinations constituted the target population while the students that sat for the selected STEM subjects (Mathematics, Basic Science, and Basic Technology) within the years under review constituted the sample for the study. The results of these students were collected and analyzed using Microsoft Excel with its in-built trend line capabilities. The results showed that students performed well in the selected STEM subjects in the years under review. Furthermore, the study revealed that while performance in other subjects will continue to improve steadily, performance in mathematics will dwindle between 2016 and 2018 and then will begin to steadily improve from 2019 to 2020. It is recommended that the government should continue to support teaching and learning of STEM subjects in all tiers of education.