This study investigated that effect of Think-Pair-Share (TPS) instructional strategy on students' academic performance in chemical equilibrium in Karu Township, Nasarawa State. Two research questions and two null hypotheses guided the study. The study adopted a quasi-experimental design, specifically the non-equivalent, non-randomized, pre-test/post-test control group type. The population of the study comprised 1220 (710 males and 510 females) Senior Secondary II students in the 39 public schools that offered Chemistry in Karu township of Nasarawa State.

The sample consisted of 76 (41 males and 35 females) students offering Chemistry. The study employed a multi-stage sampling procedure to select participants. Chemical Equilibrium Achievement Test (CEAT) questions adapted from past WAEC questions were used to collect data. The validated CEAT was tested for internal consistency using the Kuder-Richardson 20 (KR-20) formula, resulting in a coefficient of 0.74. Teaching of chemical equilibrium was done in the two intact classes by trained research assistants. The research questions were answered using descriptive statistics of mean and standard deviation, while Analysis of Covariance (ANCOVA) was used to test the null hypotheses at 0.05 level of significance.

The study revealed that students taught chemical equilibrium using the TPS instructional strategy performed significantly better than those taught using discussion method [F (1,86) = 378.480; p = 0.000 < 0.05]. However, there was no significant difference in the performance of male and female students taught with the TPS strategy [F (1,33) = 1.069; p = 0.309 > 0.05]. It was recommended among others that Chemistry teachers should use the TPS strategy to improve students’ understanding and academic performance.