Sustainable efficient lighting has become as one of the most important issues in the office environment In Sweden, energy demand for lighting corresponds to 20% of the total electricity used in office buildings (1), while It has been estimated that lighting accounts for about 20% of the total power generation of the world (2). This thesis investigates how to make lighting in offices more sustainable and focuses on energy efficiency, to save energy through creating guidelines related to light source technologies, lighting control systems and the user preferences. Then those guidelines are applied to an existing office through suggesting a new lighting design. The existing office in this case is the ÅF company 10th office floor located in Stockholm, Sweden. This investigation methodology consists of two main parts literature review and Project (case) study. In the first part, methods used are a combination of literature review related to saving energy through sustainability in lighting and how light source technology, lighting control systems and the effect of user behavior could help to create more energy efficient lighting systems. In the second part, the methods are qualitative such as surveys, quantitative methods and personal observations. The used methods helped to create guidelines for the new suggested lighting design for ÅF 10 th office floor part. The Results shows that the new suggested lighting design saves energy up to 31.96% more than the current lighting situation