Recently, social network sites have been experiencing tremendous growth, such as Facebook has about 500 million active users worldwide. Researchers have started to investigate Facebook use and its relationships with other social activities. The purpose of this research is to explore possible relationships between personality, social network sites usage, and leisure activities. A conceptual model about the possible relationships was proposed. A survey is in the process of development and the authors hope possible findings can improve our understandings of interactions between personality, use of social network sites, and leisure activities.