What, on realising disagreement, is an agent justified in believing when it comes to the substance of that disagreement? What significance ought we to afford disagreement in the practices by which we came to hold the beliefs over which we disagree? What do we do when the disagreement reaches down to the norms that determine the kinds of things we see as reasons for belief? In this thesis I employ the methodological lens of ‘peer disagreement’ to develop a response to these questions that I call the ‘Higher-Order Trust’ approach to disagreement. There are two important aspects to this position: First, I suggest that a satisfactory theory of disagreement must consider both ‘The Problem of Ordinary Disagreement’ – roughly, the question of how epistemic peers ought to respond when they disagree in so far as they hold conflicting beliefs – and ‘The Normative Problem of Deep Disagreement’ – roughly, the question of how peers ought to respond when a disagreement in beliefs is explained by the disputants following conflicting epistemic norms. Secondly, I suggest that the realisation of disagreement affords one higher-order evidence about the epistemic practices by which one came to hold the relevant beliefs. Thus, the question of how one ought to respond to the realisation of disagreement depends upon whether one has available some form of epistemic self-trust in the practices drawn into question. To understand the normative significance of disagreement, then, we first have to understand what it means to have epistemic self-trust. In this light, I suggest that there is a form of affective self-trust that can be available in cases of ordinary disagreement and realised deep disagreement between peers. When such trust is available, it may be rational to stay steadfast in the face of disagreement. Where it is not, one should respond in more conciliatory fashion.