The objectives of this research was to find the expression of flouting and violating towards maxim of quality in My Sister's Keeper novel through major characters' utterances and also to find the purposes of using flouting and violating toward maxim of quality. This analysis includes to descriptive qualitative method. This researcher used My Sister's Keeper novel as the source of data. The data derived from the utterances of major characters containing the elements of flouting and violating towards maxim of quality. From the finding of this analysis, the elements of flouting and violating towards maxim of quality were found in major characters' utterances through five strategies. They are hyperbole strategy, metaphor strategy, irony strategy, banter strategy, and lie strategy. Metaphor strategy was often used by major characters in this novel. It occurred because through metaphor strategy the characters can emphasize the point of talk to express their opinion clearly. From the analysis of five strategies, it found that there are seven purposes of using flouting and violating towards maxim of quality.