This study investigated the Impact of Adaptive Learning on Senior Secondary II Chemistry Students’ Achievement and Retention in Jos East Local Government Area of Plateau State, Nigeria. The study used Lev Vygotsky’s Constructivist Theory (1978) as theoretical framework. The study was guided by four specific objectives. Corresponding research questions and hypotheses were formulated to address these objectives. The study used quasi-experimental research design. The total population of the study comprised 1,200 SS2 Chemistry students drawn from 15 public secondary schools in Jos East. A sample size of 120 students was purposively selected from two comparable public schools—Experimental School, which received the adaptive learning intervention, and Control School, which continued with the lecture method. Pre-test, post-test, and retention test instruments were used to collect quantitative data on student performance. The mean score was used to answer the research questions while the ANCOVA was employed to test the hypotheses. The findings revealed that students taught using adaptive learning strategies significantly outperformed those taught using the traditional lecture method in both academic achievement and knowledge retention. Furthermore, no significant gender differences were observed in the achievement scores of students exposed to adaptive learning, indicating its effectiveness across both male and female students. Also, the study found meaningful differences in performance between the two schools, highlighting the role of instructional methods in shaping learning outcomes. In conclusion, this study provides evidence for the integration of adaptive learning techniques into the secondary school chemistry curriculum. It recommends policy support for digital learning innovations and teacher training to enhance adaptive instructional delivery.