Digitalization brings the opportunity for businesses to establish themselves and build their brand online. Social media streamlines communication between business and consumer and allows companies to analyze and understand their target audience more easily. The aim of the study was to increase the understanding of how companies work with brand building in social media to generate engagement. The study uses a theoretical framework consisting of theories related to branding and social media. Using a qualitative research method with a deductive approach, individual interviews were conducted with three case companies. This was done with the aim of studying the topic more closely and gaining a deeper understanding of how the case companies work with social media. Observations were also made on the companies' social media sites to confirm the empirical findings. The theories and the collected data were analysed using within-case and between-case analysis. The study has demonstrated that social media can be used as an effective tool for brand building and reaching out to their consumers. The various platforms make it easier for companies to create a personal relationship with their target audience which can result in high engagement and actual purchases.