Actual behaviour is influenced in important ways by moral emotions, for instance guilt or shame. The framework of dynamic psychological games allows the economic modelling of such emotions. Our experimental study uses psychological scales to measure individuals’ dispositions to experience guilt/shame and analyses the role these emotions play in a partnership situation that features moral hazard. We find that – in addition to second-order beliefs and promises – individuals’ disposition to guilt (specifically, their proneness to respond in an evaluative way to personal transgressions) is an important determinant of pro-social behaviour.