In recent years, writing assessment has garnered significant attention from researchers. In this regard, human rating performance has become an important area of investigation as it is influenced by different variables. Rater-related factors, including but not limited to experience, language background, interaction with a rating scale, attitudes, and perceptions have been cited. The present study aimed at investigating the effect of emotional intelligence (EI), as another aspect of raters’ characteristics, on the rating behavior of raters during the assessment of writing compositions. To this end, eight experienced Iranian EFL raters at Persian Gulf University (PGU) in Bushehr by convenience sampling. The participants filled out the Trait Emotional Intelligence Questionnaire-Short Form (TEIQue-SF) developed by Petrides and Furnham (2006) and then, they were divided into two groups of high-EI raters and low-EI raters based on their test scores. The study adopted a mixed-method research design. Subsequently, the rating behavior of raters was examined through Think-aloud protocols (TAPs) which elicited the raters' cognitive processes. They were asked to verbalize their thoughts while scoring two essays written by B.A. students by means of the analytic scale of Jacob et al. (1981). Upon content analysis of the think-aloud protocols, results revealed a different performance in the rating behaviors of high and low EI raters. The findings are discussed with regard to the previous literature as it has provided further insights and recommendations for future studies in this field. Moreover, this study offers several implications for writing assessments and the enhancement of rater training programs that behoove them to more be aware of their rating behavior.