Twitter is one of the social media networks used for the benefit of each user, either to express themselves, communicate or seek / obtain information. The purpose of this study is to find out the language functions contained in the social media network Twitter. This type of research is qualitative descriptive research, which is describing the data obtained. The data was taken through the Twitter application by looking at several tweets and tweet replies by Twitter users in January-May 2021. The data analysis in this study was conducted in several techniques, namely the first, identifying data from the data source used. Second, classify the identified data. And lastly, it concludes the results of the classification of data to find out the language functions used by users of the social media network Twitter. Based on the results obtained that found language functions in social media networks Twitter is a function of puitik, emotive, conative, fatik, referential, and metalingual language. Each of these functions is still scrutinized from some social media users Twitter through tweets (tweets) as well as tweet replies.