Guided by Expectancy Value Theory (EVT), we investigated the association of students' engineering self-efficacy and subjective task values (attainment, intrinsic, utility and cost) to four achievement-related behaviours: choice to take more engineering courses, effort in academic tasks, persistence to complete engineering tasks in the face of difficulties, and continuation in the field of engineering. Participants included 163 engineering college students from a large southern metropolitan university in the United States. Bivariate correlations and multiple hierarchical regressions were conducted to examine the relationships among variables. Results showed that engineering self-efficacy and subjective task values (except cost) were positively associated with achievement behaviours respectively. However, once the set of subjective task values were entered in the regression models, self-efficacy did not explain significant unique variance for any of the achievement-related behaviours. Intrinsic interest emerged as the most consistent predictor of achievement-related behaviours when controlling for self-efficacy and the other four task value dimensions.