Locus of control in the context of education refers to the types of contributors or attributions of success and failure and thus can affect the academic achievement of an individual. The purpose of this study is to identify the dominant locus of control among secondary school students in Brunei Darussalam and the relationship between their locus of control and their academic achievement. In addition, the study also aims to identify differences in mean scores of students’ locus of control based on the types of school, gender, year / level of study and their age. This study used quantitative approach whereby the data was analysed using descriptive and inferential statistics. Sample consists of 915 students in Year 9 and Year 10 in three government schools, in Brunei Muara District. For this research, questionnaire was used to collect data. The items in the questionnaire were adapted from Weiner (1992), Rotter (1966) and Jerabek (1996). A pilot study was conducted to obtain statistical reliability of the instrument using Cronbach Alpha and Alpha values obtained was 0.871. Descriptive analysis was used such as mean, percentage, standard deviation and percentages. In addition, inferential statistical analysis such as t–test and ANOVA were used to identify differences in mean between locus of control scores of students with regard to the types of school, gender, year / level of study and age and correlation was analysed using Chi Square test to identify the relationship between locus of control and academic achievement of the students. The results showed that the dominant locus of control among students is internal locus of control. The study also showed that there was no significant difference between the scores of students’ locus of control based on the types of school, gender and age. On the other hand, this study also showed that there was a significant difference between the scores of students’ locus of control based on the year / level of their study. In addition, the results also showed that there was no significant relationship between locus of control and academic achievement of the students.