This experimental study investigated the effect of an intervention based on Marzano’s New Taxonomy of Learning Objectives on academic achievement in mathematics among seventh-grade students by employing the Solomon Four-Group Design. A public sector girls’ school in the Haripur district of Khyber Pakhtunkhwa province, Pakistan, was purposively selected, including 247 seventh-grade students. Four groups were randomly chosen, totaling 200 students for the study sample. The intervention incorporated the self-system and metacognitive systems of thinking outlined in Marzano’s New Taxonomy of Learning Objectives. The research instrument comprised sixty multiple-choice questions from the Grade VII mathematics textbook. A t-test was employed to compare pre-test scores and to analyze both dependent and independent samples from the pre-and post-tests. The intervention significantly improved the academic achievement of seventh-grade students in mathematics in three months. The findings of this study imply that integrating Marzano's New Taxonomy into mathematics instruction can serve as an effective pedagogical strategy to enhance students' academic achievement and promote deeper cognitive engagement in learning.