The objective of the present study was to evaluate the effectiveness of a two-year intervention program to promote emotional intelligence (EI) at school. Participants were 228 primary school pupils between 10 and 11 years old. This study evaluated the effects of the intervention using a pre- and post-experimental design with a control group and four evaluation moments. EI was assessed with the EQ-i:YV questionnaire by Bar-On and Parker (2000), adapted to Spanish by Ferrándiz, Hernández, Bermejo, Ferrando, and Sáinz (2012). The results showed the effectiveness of the intervention, highlighting an increase in all the EI dimensions of the Bar-On model: intrapersonal, interpersonal, stress management, adaptability, and general mood. These findings suggest that EI can be improved. Results are discussed, and recommendations are made for future implementation.