In this study, it was aimed to develop a valid and reliable social network addiction scale for adolescents and young adults. In the Exploratory Factor Analysis of the scale, the application was conducted to 425 high school students between 14-17 years of age and 310 young adults between 18-43 years of age. Confirmatory Factor Analysis was performed on a different group and for this purpose, 322 high school students and 197 young adults were included in the analysis. As a result of the analyses performed, the scale exhibited a-10-item and three-factor structure in both groups. The total variance explained was 71.51% for adolescents and 70.96% for young adults. The total Cronbach Alpha reliability coefficient of the scale was 0.87 for adolescents and 0.84 for young adults. With the 1st and 2nd level Confirmatory Factor Analysis performed on a similar study group, a good model was revealed for both adolescents and young adults. The Social Network Addiction Scale developed within the scope of this study is thought to have the adequate validity and reliability structure that can be used to measure social network addiction levels of adolescents and young adults.