Students successfully completing an International Baccalaureate (IB) Diploma course of study may, under certain conditions, be awarded a Bilingual Diploma. Since many students in international schools may be expected to be bilingual, and bilingualism, properly nurtured, has been shown to have metalinguistic and cognitive advantages, it would be advantageous for bilingualism to be a common thread through the IB Primary Years Programme (PYP), Middle Years Programme (MYP) and Diploma Programme (DP), and to be suitably acknowledged and rewarded. This article will investigate the treatment of bilingualism in the IB, give a background to research showing the advantages of well-nurtured bilingualism and make recommendations for amendments.