Despite recent reform efforts such as the Next Generation Science Standards, students in secondary science classrooms are rarely offered opportunities to participate in authentic science practices (NRC,2007, 2011; Windschitl et al., 2008). I argue that reframing learning expectations around participation in science practices requires that students take up the ability to design and use epistemic resources, to co-construct knowledge, and to co-develop epistemic practices with the teacher and each other in a community over time. I define the shift from passive recipient of information to co-participant in knowledge and practice construction as epistemic agency (Ahlstroms, 2010; Damsa et al., 2010; Dotson, 2012; Fricker, 2007; Scardamalia, 2002; Stroupe, 2014; Tollefsen, 2004).