This cross-sectional study examined the links of social-emotional competencies (SECs: emotional regulation, relationship skills, and planning of schoolwork) with emotional well-being (EWB) and academic engagement (behavioral and emotional) among 1085 lower secondary school students. A latent structural model was tested using Mplus. The model specified the SECs as the independent variables, EWB as the intermediate variable, and behavioral and emotional engagement as the dependent variables. In line with hypotheses, the SECs showed statistically significant links with EWB; the strongest for emotional regulation. In addition, EWB was significantly associated with both dimensions of academic engagement and planning of schoolwork was directly associated with the engagement variables. The findings support the notion that EWB is linked to academic engagement and that SECs, especially emotional regulation can promote academic engagement via EWB. Yet, skills in planning schoolwork emerged as the SECs with the greatest likely potential for promoting academic engagement among adolescent students.