Interactive whiteboards (IWBs) have been widely used in elementary schools in Taiwan. Hence, the purpose of this study was to investigate the perceptions of elementary school teachers and students using IWBs in English teaching and learning. Six public school English teachers and 614 students of 5th and 6th-grades in Yangmei Township, Taoyuan County in the northern Taiwan participated in this explanatory mixed research design. For the qualitative research method, 6 English teachers were interviewed individually for 30 minutes per time, 3 times for whole interview procedure in regard to their perceptions about using IWBs which focused on the effectiveness of implement, pedagogy change, classroom interaction and students' engagement and achievement; for the quantitative research method, participants were given a questionnaire concerning their opinions and attitudes toward using IWBs. Additionally, the reason of using mixed research method was to explain students' opinions and teachers' perceptions in details toward using IWBs in English as Foreign Language (EFL) classes. Results of the study indicated that (1) teacher's master of IWB technical skills and professional knowledge of achieving teaching objectives determined the effective use of IWBs, (2) the versatile and abundant teaching and learning resources provided by IWBs led changes in pedagogy to a vivid and lively way, (3) the interaction between teachers and students have increased through using IWBs in classroom activities, and (4) students held positive attitudes that IWBs enhanced their involvement and maintained concentration in class. Moreover, students were attracted to the games related to learning English supplied by IWBs, (6) On the negative perceptions from teachers and students were the disturbances of technical problems during class and limited access time to IWBs for students.