The academic achievement, of children and young people is an issue that concerns governments in many countries. In Nigeria, students’ performance on standardised examinations has been troublingly low, especially among those from the north of the country. Previous studies on students’ achievement have focused on inadequate funding, infrastructural decay, parental background factors and pedagogical issues. However, this study considers the psychological aspects of attainment, looking at the relationships between self-concept, locus of control, school motivation, academic achievement and other contextual factors (such as gender) that are likely to have an impact on students’ performance in school. The aim is to identify some of the factors contributing to low performance in order to generate empirical evidence to inform policy and practice. The study adopts a cross sectional research design with a sequential mixed method approach to data collection and analysis. Standardised questionnaires are used to measure key concepts in the first stage. The sample consists of Secondary School Students (SS1) from public schools in Kaduna State, Northern Nigeria. Semi-structured interviews are then used in the second stage to probe the factors influencing students’ performance. The results indicate high, moderate, and low levels of relationships between academic achievement and the conceptual variables, and that self-concept and mother’s profession are the main predictors of academic achievement. The study recommends that education practitioners and policy makers develop intervention programmes in order to enhance students’ adequate and positive perceptions of their academic abilities. These might include the use of tangible and non-tangible reward systems to reinforce academic and social accomplishments, the development of policies aimed at eradicating poverty so that families can make adequate provision for their children at home and at school. The government needs to improve school infrastructure to facilitate effective teaching and learning, and enhance the students’ personality attributes.