This study aims at identifying the impact of the use of social media on the performance of the information specialists in the Main Library of Sultan Qaboos University (SQU), concentrating on the role of positive emotions and social support that result from the use of social media in influencing the performance of information specialists. To achieve its objectives, the study has utilized a quantitative approach, using the questionnaire as a tool for data collection, which was prepared based on previous relevant studies and was evaluated by experts. The population of study is composed of 75 information specialists of the SQU Main Library. The questionnaire was distributed manually to all members of the study population, and 57 valid questionnaires were returned and used to establish the results of the study accounting for a response rate of 76%. Finding revealed that the information specialists in the main library use the most popular social media. They also believe that the use of social media has social and professional benefits and that the use of these sites has its own social and professional advantages, and that they tend to use them for work purposes and to reinforce relationships with colleagues inside and outside the library. However, the results have shown that the information specialists' use o fsocial media was limited during official working hours as they tend not to spend much time using these sites during official working hours. The results have also revealed that social media sites prove influence average on the positive emotions and social support of the Main Library information specialists. The results have expressed acceptance of the hypotheses that there is a positive impact of social media use on job performance, and there is a positive impact of positive emotions and social support of the social media use on the performance of information specialists in SQU Main Library. The study came out with a number of recommendations, namely the SQU Main Library Human Resources officials most pay due attention to social media by increasing the training courses and workshops to interpret features and tools of social media, raise awareness of the positive aspects of these sites, and show their impact on the information specialists' job performance, thus motivating them to use social media in the professional development and in the creation of channels of communication amongst the Library information specialists through the different social media sites to enhance and develop social capital in the library.