We investigate the rapid influx of overseas students into UK higher education and the impact on the number of domestic students. Using administrative data since 1994/5, we find no evidence of crowd out of domestic undergraduate students and indications of increases in the domestic numbers of postgraduate students as overseas enrolments have grown. We interpret this as a cross-subsidisation and establish causal findings using two methods. Firstly, we use the historical share of students from a sending country attending a university department as a shift-share instrument to predict enrolment patterns. Secondly, we use a change in Chinese visa regulations and exchange rates in combination with strong subject preferences as a predictor of overseas student growth. The following are appended: (1) Additional Figures and Tables; and (2) Data Description. [This paper was produced as part of the Centre's Education & Skills Programme. The Centre for Economic Performance is financed by the Economic and Social Research Council.]