Intuitively, physicalism is the thesis that there’s nothing ‘over and above’ the physical. Going beyond this intuitive formulation requires an account of what it is for a property, kind, relation, or object to be a physical one. Here I defend an unfamiliar implementation of the familiar strategy of defining physical properties, etc. as those posited by the complete and ideal physical theory. That implementation ties being a physical theory to being a theory with the hallmarks of scientific theories and then identifies physical theories among the scientific ones by their characteristic subject matter, roughly, the world’s relatively fundamental elements. I then argue that, fully fleshed out, such an account is able to satisfy an array of constraints on any account of the physical, as well as avoid a number of prima facie objections, without imposing Wilson’s No Fundamental Mentality Constraint.