This study aimed at examining the relationship between Emotional Intelligence (EI) and learning English language vocabulary. The male (N= 119) and female (N= 98) participants who were randomly selected from high schools in Zanjan Province were asked to complete a Persian version of an emotional intelligence (EI) questionnaire and answer a vocabulary achievement test. The EI questionnaire consisted of 90 items that examined fifteen components of EI. The vocabulary test battery contained 40 items in various test formats that was developed on the basis of an official high school textbook. The results of the study showed a low and negative correlation between the students’ emotional intelligence and vocabulary knowledge. This finding, which is not consistent with earlier studies, implies that the contribution of EI to vocabulary learning is controversial. The results also showed that male and female students are significantly different from each other in performing on some components of EI. This indicates that the emotional capacity of male and female students has been developed differently. Moreover, these emotional capacities can be employed in a different way in the processes of language learning in general and vocabulary learning in particular.