This study investigated the impact of motivational strategies on Biology learning outcomes among SS1 students in selected secondary schools in Aba Metropolitan Area using a pre-test post-test quasi-experimental design. The purpose of the study was to determine how the application of motivational strategies such as praise and reinforcement, goal-setting, instructional feedback, and group-based rewards could influence students’ academic performance, interest, and participation in Biology. A sample of 120 Senior Secondary School One (SS1) students was selected through stratified random sampling from four secondary schools. The instrument used for data collection was the Biology Achievement Test (BAT), which was validated by experts in science education and reliability established using the Kuder-Richardson formula 20, yielding a coefficient of 0.87. Data were collected through pre-test and post-test administration over a period of six weeks. Descriptive statistics such as mean and standard deviation were used to answer the research questions, while analysis of covariance (ANCOVA) was employed to test the hypotheses at 0.05 level of significance. Findings revealed that students exposed to motivational strategies performed significantly better in Biology than those taught through the conventional method. Furthermore, the study found that motivational strategies enhanced students’ interest and participation, thereby improving their overall learning outcomes. The study concluded that motivation plays a crucial role in sustaining learners’ engagement and academic success in science-related subjects. It was recommended that Biology teachers adopt diverse motivational techniques—such as praise, feedback, goal-setting, and learner-centered reinforcement—to improve students’ learning outcomes and attitudes toward Biology.