This research analyzes the occurrences of maxim violations produced by the characters in the movie Confessions of a Shopaholic and their impacts on the effectiveness of communication. The objects are the maxim violations found in the utterances of the characters, the reasons behind those violations, and their impacts on effective communication. Those data were taken from a movie Confessions of a Shopaholic which was released in 2009. This is a qualitative research using content analysis as the method. Data were analyzed using framework of Cooperative Principle and Effective Communication theory. The research findings show that there are 40 utterances containing maxim violations which produced by all characters: 19 times violated maxim manner (47.5%), 9 times violated maxim quantity (22.5%), 9 times violated maxim quality, and 3 times violated maxim relation (7.5%). The characters violated the maxims with different reasons and contexts. Moreover, maxim violation that affect the effectiveness of communication the most is violation of maxim relation, followed by violation of maxim quantity, manner, and quality. It is implied that maxim violation holds an important role in maintaining the effectiveness of communication. It seems that the less of maxim violations occur, the more effective communication is ensued.