Although colors have such an important affect on our lives, we often take them for granted and don’t realize how much of an impact they have on us. In the final thesis, the importance of additive primary colors on the web was explored. In the theoretical part of the thesis, it was examined what colors are and how they influence us. Psychology of colors studies the influence of color on humans and their behaviour. Moreover a research on what people associate red, blue, and green with was done. In the practical part, websites were analyzed and connections between the types of websites with additive primary colors were searched for. The obtained results were gathered into tables and formed conclusions about the meaning of red, blue and green online. Blue is most commonly used and widespread. The color red is the least popular for websites. Green is the most used color for Slovenian websites associated with nature.