Relationships between approaches to learning and achievement in mathematics are well established in the foreign literature. However, studies on relationships between approaches to learning and achievement in mathematics in Nigerian mathematics education community are scarce. Thus, the goal of the present study is to showcase empirical evidence for a predictive association between approaches to learning and achievement in mathematics in Nigeria. The current study deploys a cross-sectional survey research design that includes 1260 senior secondary school year two students. Two valid and reliable instruments were used for data collection in the study. Two research questions were stated within the area of students’ learning approaches and answered using Pearson product moment correlation and step-wise regression analysis. The results showed that there was a significant relationship between approaches to learning and achievement in mathematics (r = 0.433, p < 0.05). Moreover, all associations were significant between deep approach (r = 0.673, p < 0.05), surface approach (r = −0.251, p < 0.05), strategic approach (r = 0.516, p < 0.05) and achievement in mathematics. The ANOVA regression analysis revealed a significant association between deep approach, surface approach, and strategic approach with achievement in mathematics (F(3, 1256) = 399.35, p = 0.000) and the three approaches to learning jointly contributed as much as 48.7% variance to achievement in mathematics. The deep approach recorded the greatest beta (β) value (0.549), trailed by strategic approach (β = 0.151), and the least was surface approach (β= −0.161). The equation of the regression analysis is depicted as: Achievement = −4.294 + 0.282 deep approach − 0.065 surface approach + 0.063 strategic approach. Findings were discussed, implications of approaches to learning were made and some recommendations for future studies stated.