The effect of first language transfer on second language acquisition and learning has been a major theoretical concept in second language research and pedagogy since the 1950s. In order to give a historical perspective, the authors offer a brief presentation of some of the major topics from the broad spectrum of issues that have been examined by the applied linguistics research community during the past six decades and some significant developments in neuroimaging and cognitive science that have allowed researchers to investigate the role that first language plays in transfer to second language during neural activity and cognitive processing. The paper concludes with some pedagogical implications for second language instructors.