There had been a growing concern among educators and other stakeholders on the successful implementation of the History and Government curriculum. Data on students’ performance in History and Government at secondary school level indicated that the implementation of the curriculum was not as envisaged. Thus statistics of Kenya Certificate of Secondary School Examination (KCSE) of 2019 revealed that 69.13% of candidates in Kenya took history and government in 2019 KCSE examinations and the mean score of the subjects nationally was 4.1 which is a D+ according to the grading system. Students’ performance in Emuhaya Sub-county had been low for the years from 2016 to 2019 where performance was; 3.59 lower than the neighbouring sub-counties, that is Hamisi, 5.33; Vihiga, 4.72; Sabatia, 5.12 and Luanda, 4.25 Sub- Counties. The objective of the study was to determine the influence of students’ entry behavior on the successful implementation of History and Government Curriculum in Secondary schools in Emuhaya Sub County, Kenya. A conceptual framework postulating the influence of the students’ entry behavior (Independent Variable) on the implementation of History and Government Curriculum (Dependent Variable) was used to focus on the objective of the study. The findings of the study indicated that students’ entry behaviour accounted for 13.7% of KCSE History and Government mean score. This means that the students’ entry behavior contributed for 13.7% to the successful implementation of History and Government in secondary schools. 86.3% was the contribution made by other factors that were not subject of the study. These factors included teaching learning resources, teachers’ qualifications, school infrastructure, teachers’ attitudes among others. The study concluded that the entry behavior of students significantly influenced the successful implementation of History and Government curriculum at secondary school level. The findings of this study are significant to the Ministry of Education and School Boards of Management in formulation of policies that can enhance implementation of History and Government Curriculum. The findings also form baseline information for further studies in related areas.