This study evaluates the effects of a psychoeducational training program on the development of emotional intelligence in preschool and elementary educators and caregivers. Theories of emotional intelligence (EI) are applied to practical issues of adult EI education and assessment in the workplace. The study site was an early childhood center and school serving a low-income Hispanic neighborhood. The 17 participants were primarily Spanish-speaking immigrant women, most with limited formal educations, who took 60 hours of Nurturing Peace in Early Childhood training. The intervention was designed to develop their ability to perceive, understand and manage emotions, and to successfully implement a social-emotional learning program with children. Multiple quantitative and qualitative assessments were used, including EI ability tests, performance observations, and self-report measures. Findings suggest that, though participants' EI appeared weak pre-program, it improved significantly post-training, as did their implementation of the Peaceable Classroom program with children. The study suggests practical implications for preparing teachers to implement social-emotional learning programs, as well as for retooling tests for assessing EI in culturally and educationally diverse populations.