Terms like self-directed learning and learner autonomy, which have become prominent with the evolving interest in lifelong learning, have been interpreted differently by several researhers. These terms which started to be discussed in the field of adult education in North America In 1960s and then moved to Europe in 1980s and influenced the field of foreign language learning, have changed their meanings during this journey. In a literature review, it is seen that these terms have sometimes been used interchangeably. With the aim of helping the researchers who want to study in this field, the related literature is reviewed and the terms are explained comparatively regarding the whole process.