The main goal of the DFS data collection project is to map the online friendship networks of Dutch adolescents. Specifically, the Facebook networks of Dutch adolescents participating in the offline CILS4EU and CILSNL data collection are mapped. Facebook is an American social networking site (SNS) where users create an online profile, provide personal information on this profile and invite other users to become connected as friends. With these connections, users can interact via personal messaging, post directly on others’ personal profile pages and react to others’ posts. During the time of our data collection, in 2014, Facebook was the largest SNS of the world with approximately 1.3 billion members. The DFS data are collected to study the relationship between offline face-to-face contacts, and online friendship network on Facebook. To this purpose we coded variables that show respondents’ Facebook friends’ gender, numbers of friends, privacy settings and ethnicity.