 1. The Sedentary Behavior Research Network, SBRN, undertook a terminology consensus project to standardize terminology in sedentary behavior research. 2. A literature review was completed, followed by modifications and feedback from a steering committee and SBRN members through an online survey. 3. The project resulted in consensus definitions for key terms such as physical inactivity, stationary behavior, sedentary behavior, and screen time, which are hoped to be widely adopted to advance future research and practices related to sedentary behaviors. This article was authored by Marques Tremblay, Salomi Orbert, Joel D. Barnes, and others.