The purpose of this research was identifying the effect of emotional intelligence (EI) instruction on the work–life conflict of the female high school teachers of 19th educational district of Tehran. In this Quasi-experimental study with pre and post-test design, 50 teachers were randomly divided into two intervention and control groups with the same number (25 teachers) in each group. The research instruments were demographic questionnaire, Karlson’s work–life conflict, as well as Bar-on emotional intelligence (EQ) questionnaires. Validity of the questionnaires was confirmed and internal consistency was calculated based on Cronbach Alfa (0.90 for work-life questionnaire and 0.95 for EQ). Both questionnaires were completed by both groups of teachers (intervention/control groups) at the beginning (pre-test) and the EI instruction was given just to the intervention group of teachers for 4 consecutive weeks. After one month, the same questionnaires were again completed by both groups (post-test). To analyze the data, both descriptive statistics including mean and standard deviation and inferential statistics including independent and dependent t-tests and co-variance were used. The results showed that EI instruction had a meaningful and positive effect on the reduction in work –life conflict of teachers under study.