Social media have been increasingly used by sports organizations to establish relationships with the public. This study explored the Twitter using practices of NBA clubs (N = 30) in the United States in building relationships with their publics during the 2013-14 season.Specifically, it focused on how these clubs used Twitter as a communication tool to build professional, personal, and community relationships through a content analysis of 5561 tweets on their official Twitter sites. The results demonstrated that sports organizations tended to use social media to develop professional relationships with fans via sharing information and promoting products. They utilized several types of communication tools such as retweets, public messages, hyperlinks, and hashtags, among which hashtags were used most frequently. Professional relationships could benefit more from hyperlinks while there could be greater benefit to personal relationships from public messages and retweets and to community relationships from hashtags and hyperlinks. Sports organizations should use these tools effectively to strengthen the professional, personal and community relationship with their publics.ii DEDICATION This thesis is dedicated to everyone who helped me and supported me through the trials