The motivation of this study is to create a dataset that allows researchers to explore the online visibility and activities of all mosques and their (online) followers in the Netherlands. Data were collected from personal websites, Facebook, Twitter, Instagram, and YouTube. The data collection took place between 15th September 2018 and 1st July 2019. During this period, we collected data on the online activity of mosques in the Netherlands as well as data on their online followers.