This chapter describes the key graph-based knowledge representations needed to support moral reasoning. These express classification relations, state-act-state transition relations, causal relations and evaluation relations. Classification relations express concepts such as ‘Puss is in the class Cat.’ State-act-state transition relations express concepts such as the act ‘need to move from a state where the window is open to one where the window is closed’ is: close the window. Causal relations express relations of cause and effect. For example, being submerged will cause a human infant to have unmet needs for air, which in turn will cause death. Evaluation relations are classifications of acts or states as good or bad. A dead infant is bad compared to a living one.