In this paper it will first be discussed what the media are all about so that the definition of media literacy could be more easily understood. Media literacy in today`s modern world is indispensable for the development of the individual and his progress. The paper presents some of the literacy that an individual needs to master in order to be in the process of developing technology as well as media that are two inseparate concepts. It will also be shown research in Croatia and also in the world, like how much are Croatians literate at all, what results have the fifteen-year-olds in Croatia and in the world have accomplished about mathematical, science and reading literacy. Next are the results of research how many children use technology and media and how much their parents are conversant in that and how much an average online time people spend on their own networks and social media. Besides various researches, in the paper it will be talked about the types of media content, their positive and negative influences as well as the good and the bad sides. How much violence, stereotypes, alcohol, tobacco and drugs are represented in them, and how much they affect the audience that watches that. The most represented media today are internet and then television while the newspapers are the oldest media through which important news has been transmitted. These three media will be described in more detail with a few examples of their impact on people through history. After mastering various other literacy and investment in one`s own education, a person becomes media literate.any such person is also able to be a good critic by giving critical opinions to the various topics with whom they meet in the media. At the end of this paper, there will be words on what is actually a critical thinking any person can be good at.