This study examined the comparative effects of the Mastery Learning Strategy (MLS) and Thinking Maps Strategy (TMS) on students’ academic performance in Basic Science in Makurdi Local Government Area of Benue State, Nigeria. Three research questions were raised and translated into null hypotheses, tested at the 0.05 level of significance. A quasi-experimental pre-test, post-test, non-equivalent control group design was adopted. The population comprised 1,903 upper basic II students across 31 schools in the 2023/2024 academic session.

A sample of 76 students from two intact classes in two schools was selected through multistage sampling. Instructional content covered Basic Science topics such as energy, work, power, and energy transformation. Data were collected using the researcher-developed Basic Science Performance Test (BSPT), validated by experts and found reliable with a KR-20 coefficient of 0.94. The experiment lasted four weeks and was administered by two trained research assistants.

Data were analysed using Mean and Standard Deviation for the research questions, while Analysis of Covariance (ANCOVA) was used to test the hypotheses. Findings revealed no significant differences in performance between the MLS and TMS groups [F (1, 73) = 0.529, p = 0.469], nor between male and female students within each group: MLS [F (1, 38) = 0.007, p = 0.934] and TMS [F (1, 32) = 0.764, p = 0.389]. The study concluded that both strategies are effective in improving students’ performance. It recommends teacher training and curriculum integration of MLS and TMS to foster better outcomes in Basic Science.