The purpose of the present study was to assess the effect of academic self–concept on the syntactic complexity of speaking skill among Iranian upper-intermediate EFL learners. The sample consisted of 45 male and female students of the upper-intermediate level who were learning English language in a private institute in Isfahan. In order to collect information about students’ academic self-concept, Liu and Wang’s (2005) academic self-concept scale was used. It consists of 20 items and responses are made on a 5-point Likert scale ranging from strongly disagree to strongly agree. For speaking data collection, participants were asked to sit for speaking test (narrative story) and their speaking performances were recorded by a digital voice recorder for later transcription and analysis. Independent samples t test was conducted to find out if there were statistically significant differences between the high self-concept group and low self-concept group’s syntactic complexity in speaking. Results indicated that the former group significantly outperformed the latter on three measures of syntactic complexity including length of production units, measures of subordination, and degree of phrasal sophistication. On the measures of coordination, however, the results indicated that there were no significant differences between learners with high academic self-concept and learners with low academic self-concept. پرونده مقاله