This thesis is concerned with the development of children's concepts of anger and sadness. The way in which children's concepts of anger and sadness develop is of particular interest since they tend to be less differentiated in young children than the other negative emotions of fear and disgust. The principal focus is on one important dimension differentiating the two emotions, that of intentions. For adults, anger arises where a negative outcome is the result of a protagonist acting intentionally and sadness arises where a negative outcome occurs due to the unintentional actions of a protagonist. A series of experiments showed that 6- and 7-year-old children are only implicitly aware of a link between anger and bad intentions. They do not predict anger, or sadness, on the basis of intentions. At 8 years a significant shift occurs. Children demonstrate an explicit awareness of the anger-intention link, they predict anger on the basis of bad intentions and explain anger in terms of intentions. The link between sadness and unintentional harm is less apparent. An explanation of the shift in terms of the perceived social unacceptability of anger was given limited support. An explanation based on the development of children's causal attribution skills was more successful. In conclusion, an attempt was made to locate the changes in children's intentionrelated concepts of anger and sadness within a broader framework for understanding both children's concepts and their actual experience of the two emotions. This framework was suggested by a functionalist account of emotions