Science education reforms seek to increase student inquiry, peer collaboration, and making student thinking visible in order to better support science learning. Yet each of these ingredients assumes that students will choose to actively participate in various classroom activities. This article highlights key considerations to support agency -- or more specifically authorship of knowledge -- in science classrooms. We draw on studies that examine factors influencing students' cooperation to argue that consideration of benefit of student action relative to the cost of student action is central to supporting agency. The benefit to cost is influenced by a multitude of pedagogical decisions and classroom characteristics. Thus, we subsequently leverage what we have learned from nearly two decades of research on the Science Writing Heuristic approach to examine classroom characteristics that are central to increasing benefit and thus supporting student authorship/agency. The article concludes with suggestions for how to integrate these ideas into the classroom.