Government backed income contingent student loans are an increasingly being used to fund higher education. An income contingent repayment plan acts as an incremental marginal tax on labor earnings, which could cause individuals to distort their work effort. This paper uses an administrative dataset from the UK that links student loan borrowers between 1998 and 2008, to their official tax records between 2001/02 and 2013/14. Using a combination of techniques, including bunching and difference-in-difference methodology, our findings strongly reject the hypothesis that the UK's income-contingent repayment plan distorts labor supply. [The Economic and Social Research Council's (ESRC's) Centre for the Microeconomic Analysis of Public Policy at IFS provided financial support for this work.]