The aim of this thesis is to research and show the relations between influencers and their ethics, opinions of their followers and development of influencer marketing. Ethics, ethics in business and ethics in marketing are being described. Key areas of ethics in marketing are research, product, price, sales, distribution and communication. Marketing experts should follow rules, principles and standards of business ethics in order to be able to come up with an ethic decision. Furthermore, development of social media alongside with digitalization and research on how and why are influencers using them as their work tools are also being described. Digital technology, which is always on the increase, opened many new possibilities in online advertising. Promotions and sales over social media became a necessity rather than an option. As a consequence, in the last couple of years there has been a rise in companies using social media influencer advertising. Content created by the influencers has become more credible than any other form of marketing. Lastly, questionnaires have been conducted to depict thoughts on influencer's work as seen by their followers and friends. Conclusion is that influencers in Croatia are described as being ethic by their followers. They have a moderate influence on their followers. Even though they follow and interact with them daily, they do not trust them completely.