The current study aimed at investigating the possible effects of explicit teaching of affective strategies on Iranian EFL learners' oral language proficiency and the extent of their anxiety in EFL classroom. First, PET test was administered to a total number of 120 female third grade high school EFL students. Then, 60 participants whose score fell within the range of + or - 1 SD from the mean score were selected for the main study. Next, they were randomly assigned into two groups (one control and one experimental). The design of the study was Experimental comparison-group plan. Foreign Language Classroom Anxiety Scale adopted from Horwitz (1986) was used to examine the EFL learners' anxiety level in English class. Moreover, two equivalent oral tests adopted from Heaton (1975) were administered to the participants of the two groups both at the beginning and at the end of the study served as pre and post-tests. The treatment for the experimental group included Oxford's (1990) taxonomy of affective strategies, which included explicit affective strategy instruction (in relaxation, music, visualization, humor, positive self-talk, risk-taking, and monitoring emotions). The control group did not receive any special instruction in terms of affective strategies. To investigate the possible effects of explicit affective strategy use instruction on the participants' oral language proficiency and their anxiety level, the pre and posttests of oral tests and the participants' self-reports of anxiety control in both groups were analyzed and compared. The results of independent samples T-test indicated that while the two groups were homogeneous in terms of oral proficiency and level of anxiety control before introducing the treatment, the experimental group performed better than the control group in the oral post-test. Moreover, the level of anxiety control for the experimental group was significantly different and higher than that of the control group. The results confirm the positive effects of affective strategy instruction on oral language proficiency. The findings of this study provide a greater understanding of affective strategy use among Iranian EFL learners. This study might also have some implications for material developers to consider strategy use in materials development.