A large and increasing proportion of teaching in UK universities is being fulfilled by staff on casual, rather than permanent, contracts. This paper examines how the proportion of teaching by casual staff affected student satisfaction in 2014-15. We find that an increased proportion of casual teaching leads to lower student satisfaction, even when controlling for respondent's subject, university and faculty. This suggests a trade-off between increasing casualisation and student satisfaction, which could have implications for future student demand. These results can be generalised to the rest of the economy and highlight potential perverse effects arising from casual contracts.