The situation facing European countries after World War II provided the social and political context in which the Council of Europe began its deliberations on language and culture, deliberations that eventually led (in 2001) to the release of the current version of The Common European Framework of Reference for Languages: Learning, teaching, assessment (CEFR). Since then, the influence of the CEFR has increased steadily both within and outside of Europe. Following an introduction to the research and the rationale for it (Chapter 1), an outline of the CEFR and the political and social context out of which it emerged (Chapter 2) and a critical review of selected critiques of the CEFR (Chapter 3), this thesis reports on a questionnaire-based survey of responses to the CEFR of a sample of language teachers (Chapter 4) and an analysis of the impact of the CEFR in the area of curriculum design in two different contexts (Chapters 5 and 6), ending with and an overview of the research findings (Chapter 7). Of the 164 participants (from France, the UK, Taiwan, Hong Kong, New Zealand and Australia) who were involved in the questionnaire-based survey, only just over 20% claimed to have read the CEFR (26% in the case of those working in Europe). Over half claimed never to have heard of it (34%), to know of it by name only (5%) or to have only a vague idea of its content (19%). Of those with a view on the subject, only 31 agreed that it is becoming impossible to avoid the CEFR in the field of language teaching / learning (as opposed to 42 who did not). Asked to evaluate the overall impact of the CEFR in the countries where they worked on a six point scale (from 1 (very positive) to 6 (very negative)), 105 participants responded, with 57 (54%) selecting ‘I don’t know’. Among the remaining 47, the average rating was 3.23. Asked to evaluate the usefulness of the CEFR in the countries where they worked in a number of areas (on a six point scale - from 1 (very useful) to 6 (not useful at all)), just over 100 participants responded in each case, with just under half selecting ‘I don’t know’. For the remainder, the overall average rating was 3. These findings suggest there is little interest in, or enthusiasm for the CEFR among those frontline professionals who will ultimately determine whether it has any real impact on the teaching and learning of languages. Curriculum design was rated second in terms of usefulness in the survey (with a rating of 3.08). In order to determine how useful the CEFR actually is in this area, two different CEFR-influenced national, school-based language curriculum projects were analysed (one within Europe; the other outside of Europe). That analysis revealed a number of significant problems, particularly in relation to the articulation of achievement objectives and the association between achievement objectives and language-specific realizations. It was therefore concluded that the CEFR promises considerably more in the area of language curriculum design than it is capable of delivering.