The aim of current research is to analyze adult individuals’ levels of self-esteem, internet and social media addiction. Moreover, adult individuals’ levels of self-esteem, social media and internet addiction were investigated according to their employment and marital status, age and gender. In current research, Rosenberg Self-Esteem Test, Young Internet Addiction Test, Social Media Addiction Test for Adults, Descriptive Information Form, which were prepared by researchers were conducted for collecting necessary data for this research from the participants of 528 adult individuals. The results of the current research indicated that there are significantly negative relationships among adults’ levels of internet, social media addiction and the self-esteem; the higher their levels of self-esteem the lower their levels of social media and internet addiction. It was concluded that the adults’ addiction levels of social media and internet significantly predicted their self-esteem level. In addition, there exist significant differences regarding adults’ levels of social media and internet addiction, and self-esteem according to working and marital status and age. It was found that there is insignificant difference with regard to gender.