This essay examines how three public, Swedish museums use Instagram as a tool for encouraging social interaction and for the building of relationship with the audience. The three examined museums are Livrustkammaren, Världskulturmuseet and Moderna Museet Malmö. By using the method netnography the study has collected posts and comments from the three museums during a limited period of time (2 months). The results present both differences and similarities between the three museums’ use of Instagram. All of the museums have some degree of interaction with users on Instagram, but Livrustkammaren stands out as a museum with more interaction than the others. With the help of Erving Goffman’s theories about social interaction, Anders Persson’s interpretation of these and theories about online relationship strategies presented by Kelleher/Millerand Smith, the essay provides insight into how museums can use Instagram as a communicative tool if the museums want to increase the social interaction and improve and maintain the relationship with the audience. According to the results of this study, some of the more successful strategies are: using humour as a way of connecting with the audience and using a ”conversational human voice”, i.e. a more personal voice. The essay opens up for further studies of how museums can work with Instagram as a tool for communicating with the audience.