This article reports on the findings of a study conducted to investigate teachers' and students' perceptions of interactive whiteboards (IWBs) in the English as a foreign language (EFL) classroom and to find out differences of perceptions according to some variables such as gender, level of English proficiency, hours of weekly IWB use, and years of teaching experience. Two self-report questionnaires were used to gather main data from 58 EFL teachers and 164 EFL students in a private Anatolian high school in Ankara where IWBs were installed and actively operated by teachers in classrooms. The student questionnaire consisted of 26 five-point Likert-scale items to measure the student's perceptions about (1) Perceived Learning Contribution, (2) Motivation, (3) Perceived Efficiency, and (4) Perceived Negative Effects, whereas the teacher questionnaire included 25 fivepoint Likert-scale items to measure their perceptions about (1) Instructional Effects of IWBs, (2) General Attitudes, (3) Motivational Effects of IWBs, and (4) Need for Training. Quantitative data was further supported by qualitative data gathered from teachers through open-ended questions. The findings revealed that overall both teachers and students have favorable perceptions of the IWB technology and its benefits in EFL classrooms. However, the results of t-test and One-way ANOVA tests showed no significant difference in the teachers' perceptions of IWB use with respect to their gender and years of experience. Female and male students did not have any significantly different perceptions of the IWB technology either. However, the results of One-way ANOVA revealed that students differ in their perceptions according to their level of English proficiency and hours of weekly IWB use. Another finding indicated that teachers with more years of teaching experience had more favorable perceptions of IWBs than less experienced teachers and that teachers who use IWBs more frequently have more positive perspectives on the use of the IWB technology. Similarly, it was found that the more students got involved in using IWBs, the more their perceptions changed favorably. The results of qualitative data also supported the findings of teachers' self-reported perceptions in relation to the general attitudes on the pros and cons of IWB use in EFL classrooms. Another major finding of the study revealed that teachers need training for this technology in order to acquire the essential competencies in pre-service and inservice training programs. Further research in this area could be an investigation of pedagogical approaches to integrate IWBs in the EFL classroom.