A key opinion leader (KOL) is a person who is an expert in his/her niche and is highly regarded by others in their niche. They are the ultimate authority on a topic or field and are well-known for their expertise on the subject. They can be doctors, politicians, academicians, and other professionals who are at the peak of their careers. A KOL is not just someone who is popular, but someone who has the relevant credentials and experience to make them experts on a subject. In a nutshell, a KOL is: An expert in a field Has real credentials and not just popularity Is highly regarded by others in the industry Has the power to influence the opinions of influencers and other experts