This study investigates the quantitative influence of the Scoreboard Reward System (SRS) on the attention span of Grade 11 Senior High School students during science classes. With the integration of the Behaviorist Theory, which clearly emphasizes the use of reinforcement for desired behaviors, this study employed a quasi-experimental pretest-posttest design. The two classes used in this study were selected through purposive sampling: one as the control group—traditional instruction—and one as the experimental group—SRS intervention. Both groups underwent a 20-item pretest and posttest to measure their attention span during science class. Before the implementation of the SRS, both classes—control group (M = 11.20, SD = 2.45) and experimental group (M = 11.45, SD = 2.31)—showed similar low attention spans during science class. However, after the implementation of the SRS, the experimental group has significantly improved to a posttest mean of 17.30 (SD = 1.98), and an average increase of +5.85 points, which is equivalent to a 17.4% increase. Moreover, the independent t-test result showed a significant difference between the two classes (t = 6.78, p < 0.01), confirming positively the effectiveness of Scoreboard Reward System Generally, the results suggest that the integration of SRS is considered an effective classroom management strategy for increasing the attention span and the engagement of the students, specifically, during science class. The study offers very significant insights for educators in seeking instructional tools that positively reinforce students behavioral patterns and improve focused classroom instruction.