This study sought to examine the impact of attitudinal adaptation on academic achievement among boys and girls in boarding secondary schools in Meru County in Kenya. The descriptive survey research design was adapted for the study whose sample size was 384 students, school counsellors and deputy principals in the boarding secondary schools. The research instruments consisted of questionnaires and interview schedules. Data analysis was enabled by use of the Scientific Package for Social Sciences version 20.0. Both descriptive and inferential statistics were employed for data analysis. The findings revealed that attitudinal adaptation had a positive impact on academic achievement but there were no significant differences in the impact between boys and girls in boarding secondary schools within Meru County in Kenya. It was therefore recommended that school administrators needed to improve the image of secondary schools through rebranding, upgrading the furniture and equipment as well as maintaining the school compounds. The Ministry of Education could also set minimum quality standards for school resources such as size of rooms and nature of furniture and equipments while school counsellors could design programs geared towards helping students in general attitudinal adaptation.