The following master thesis “The Influence of Big Data on Retail Activities and Retail Performance” is aimed to define big data and big data analysis, and to evaluate its importance in a new data driven world. Furthermore, it will be investigated how big data can be used in retail activities as it is proved that the use of big data can improve retail performance. Therefore, this thesis will also present case studies of successful usage of big data analytics in retail companies where it will be proved that big data analysis can lead to an increase in sales and customer loyalty, improvement of store layout to fit the customers’ needs and many more. To see the relevance of big data in retail across the globe, a qualitative research will be made. This research will be conducted by doing a case study analysis. The goal of this research is to find out how retail companies use big data to achieve competitive advantage. The first part of the thesis will introduce the topic of big data and big data analysis along with objective of the study, research design and methodologies. The second part of the thesis deals with defining, describing, and evaluating big data and big data analysis. Furthermore, the third part of this paper will deal with the potential of using and implementing big data analytics in the retail sector as well as presenting the benefits that companies received after successful implementation of big data analysis. The fourth part of the thesis will show the empirical research along with research method, research results, limitations, and future potential of big data analysis. The final part of this study ends with the conclusion on the topic of big data analysis and the usage of big data analysis in the retail sector. Finally, list of references will be shown at the end the thesis.