Increasing the students' academic achievement in the international evaluation arena is a challenge for our country, and cooperative learning and emotional intelligence may be a solution for this problem. The link between cooperative learning, emotional intelligence, and academic achievement has been poorly studied so far. The objective of the present investigation was to examine the influence of cooperative learning on trait emotional intelligence and academic achievement. The methodology used was a quasi-experimental design with pre/post-measurements and experimental/control groups. The participants were primary education students (n = 692) and teachers (n = 24) from eight public schools in Madrid, Spain. The instruments used were the Emotional Quotient-Youth Version questionnaire and internal and external assessment tests. Our results indicated that cooperative learning improved scores of one dimension of trait emotional intelligence, change adaptability, and students' academic achievement (Mathematics and Spanish Language). We discussed the possible implications of these outcomes for educational practice.