This chapter makes the case for a research focus on English medium instruction (EMI) in Asia-Pacific higher education. Three key reasons are provided: (i) the rise in the geopolitical status of English as a lingua franca; (ii) the expansion of higher education in the region; and (iii) the boom in large-scale internationalisation education policies by Asia-Pacific governments. In this context, the very meaning of ‘EMI’ is problematized, with the binary ‘it is or it isn’t’ distinction eschewed in favour of more nuanced, situated conceptualisations, and extending to EMI in Anglophone contexts. The paper then outlines some of the key challenges relating to EMI at the governmental, institutional and classroom levels, as well as considering issues of language assessment and content outcomes. Finally, an overview of work by key researchers on EMI in Asia-Pacific is provided, focussing on: (i) EMI policies and practices in various Asia-Pacific polities; (ii) issues affecting EMI instructors; and (iii) multiple language use among learners in EMI contexts