This study was an attempt to investigate the relationships among Attention-Deficit/ Hyperactivity Disorder (ADHD) and speaking complexity, accuracy, and fluency (CAF) among Iranian EFL learners. To fulfill the purpose of this study, the teachers and parents of 593 male students were given the Farsi version of the CSI-4 ADHD diagnostic questionnaire, out of which 61 students scored above the cut-off score of nine in both the teacher and parent questionnaires. These students then sat for a sample speaking section of the Key English Test (KET); the interviews were scored by two raters according to the measures of CAF. The data were thus analyzed and the results revealed a significant positive correlation between ADHD and speaking fluency; in contrast, a significant negative correlation was observed between ADHD and speaking complexity and ADHD and speaking accuracy. The regressions disclosed that ADHD is a significant predictor of complexity, accuracy, and fluency in speaking. The findings of this study have pedagogical implications for both parents and teachers in contact with students with ADHD with respect to the importance of identifying such students and thus planning and monitoring their progress.