The International Baccalaureate (IB) organisation, through its three programmes (Primary Years Programme, Middle Years Programme and pre-university Diploma Programme), aims to develop students who contribute to a more peaceful world through promoting intercultural understanding and respect. The aim of the study on which this article is based was to examine the extent to which the International Baccalaureate Diploma Programme (IBDP) is effective at delivering the IB mission statement. Literature has first been reviewed in order to explore the aims of international education and how curricula and school systems can influence the development of values within students. Within the review, concepts are explored and compared to the IBDP. The literature review concludes with a model reflecting the influences on the promotion of international education within a school. The article then describes a case study carried out in an international school that delivers the IBDP, using a mixed methods approach with an exploratory sequential design. A small number of IBDP students were interviewed, and the findings of these interviews were triangulated using a questionnaire completed by all Diploma Programme students in the case study school. The results of the student interviews and questionnaires were used as the basis for ascertaining the ways in which the IBDP has influenced student attitudes.The study concludes that the values of the students in question were moving towards those expressed in the IB mission statement. The significance of different elements of the school curriculum and the school environment for the development of values within the student population has been highlighted as an area for possible further research.