The purpose of this study was to examine the effects of instructional materials in teaching and learning of Geography in Public Secondary Schools in Nandi North Sub County, Nandi County. It was guided by the following objectives; to investigate how Information and Communication Technology (ICT), influences the teaching and learning of Geography in Public Secondary Schools; to examine the use of maps in teaching and learning of Geography in Public Secondary Schools; and also to examine the challenges faced in using textbooks in teaching and learning of Geography in Public Secondary Schools. The study used descriptive survey design and adopted the quantitative approach. The study comprised of a total of 101 respondents constituting of 90 students and 11 Geography teachers from Nandi North Sub County, Nandi County. The data collected was organized and analyzed using the Statistical Program for Social Sciences (SPSS) The study found out that most of the schools had diverse instructional materials used when teaching and learning of Geography like maps, projectors, televisions, computers, textbooks and good internet connections.Although the use of maps and Projectors was poor with (60.9%) of the students reporting the unavailability of it hence, negatively impacting the teaching and learning of Geography, while the most crucial, that is Geography textbooks were adequate with (71.3%) of the students responding about it thus positively impacting the teaching and learning of Geography. The study recommends that students should be taught with various instructional materials to ensure the effecting teaching and learning process and to the government and the school administrators, they should ensure that the school has adequate instructional materials and also Geography laboratories to provide space for the teachers and students to access the instructional material easily. The study concluded that the use of instructional material has a positive influence in the teaching and learning process of Geography.