Despite much interest and investment in the Internet of Things (IoT) which expand the Internet to a ubiquitous network including objects in the physical world, there is growing concerns of privacy protections. Because the risk of privacy invasion is higher in IoT environments than ever before, privacy need to be a key issue in the di!usion of IoT. Considering that the privacy concern is a critical barrier for user to adopt information technologies, it is important to investigate users’ privacy concerns related to IoT applications. From the triad perspective (i.e., risk on technology, risk on service provider, and trust on legislation), this study aims to examine users’ privacy concerns in the context of activity trackers.