This toolbox highlights thinking routines developed across a number of research projects at Project Zero (PZ). A thinking routine is a set of questions or a brief sequence of steps used to scaffold and support student thinking. PZ researchers designed thinking routines to deepen students’ thinking and to help make that thinking “visible.” Thinking routines help to reveal students’ thinking to the teacher and also help students themselves to notice and name particular “thinking moves,” making those moves more available and useful to them in other contexts.