This thesis studies the labour supply with aspiration-based reference-dependent preferences. The first contribution of the thesis is the theoretical modelling of behavioural contract theory. In Chapter 1, I modify the classical principal-agent model with uncertainty and moral hazard by replacing the Expected Utility preferences of the agent with chance theory preferences (Schmidt and Zank, 2013). Chance theory agents are primarily concerned with the sure wage they can obtain, i.e., the certain component in their contract, as they treat increments in bonuses markedly different to similar changes in sure wages. Similar to the classical predictions, our agents' optimal contracts are contingent payment schemes, however, they differ with respect to the level of the sure wage. I also contrast my predictions to those of the model of Herweg et al. (2010), who assume agents with expectation-based loss-averse preferences. The other contribution of this thesis is the empirical support for the theory of aspiration-based reference-dependent preferences with field data in education economics. In Chapter 2, I study aspiration-based reference-dependent preferences in undergraduate students' performance and effort provision. Students' reference points are set as their targeted grades. I extend a two-period economics-of-education model (Krohn and O'Connor, 2005) by proposing an additional utility function that is based on the difference between the realised grade and targeted grade. I design surveys and collect data by following a group of undergraduate students at the University of Manchester for two semesters of a full academic year with a two-period panel. My results provide evidence for students' reference-dependent preferences in two ways: first, a significant jump in students' proxied utility of grade is found at the reference point, which also implies students are loss averse. Second, the reference point positively affects students' effort provision. I further study the formation of the reference point and its variation over time. My results suggest that students partially update their past realised results into the formation of reference points. Further, the relative change of their reference points depends on the achievement of the past period reference point.