The present study aimed to investigate the relationship among assertiveness, self-consciousness, and L2 oral ability of Iranian intermediate EFL learners. To this end, 45 intermediate EFL learners were selected by convenience sampling. The participants were provided with Self-consciousness Scales and Rathus Assertiveness Schedule to determine their level of self-consciousness and assertiveness. Afterward, an interview was conducted to assess their L2 oral ability so 10 to 15 questions were asked during a twenty-minute interview. Finally, Kanda Group Oral Discussion Test Descriptor Bands were used for assessing the students’ L2 oral ability in terms of pronunciation, fluency, grammar, vocabulary, and communication skills. The results revealed: (a) a negative correlation was found between self-consciousness and L2 oral ability, (b) a positive correlation was found between assertiveness and L2 oral ability; (c) among the five constructs of oral ability, the highest level of assertiveness was related to communication skills, (d) the highest level of self-consciousness was negatively related to communication skills, pronunciation, and vocabulary, respectively, and finally, (e) private self-consciousness influenced L2 oral ability more than public self-consciousness. The findings of this study shed light on the importance of individual differences in L2 language learning, i.e., this study reminds English teachers to be aware of individual differences in their classrooms, and they are recommended not to attribute their students’ failure only to whether they can learn L2.