We propose a novel definition of binders using matching logic, where the binding behavior of object-level binders is directly inherited from the built-in ∃ binder of matching logic. We show that the behavior of binders in various logical systems such as-calculus, System F,-calculus, pure type systems, can be axiomatically defined in matching logic as notations and logical theories. We show the correctness of our definitions by proving conservative extension theorems, which state that a sequent/judgment is provable in the original system if and only if it is provable in matching logic, in the corresponding theory. Our matching logic definition of binders also yields models to all binders, which are deductively complete with respect to formal reasoning in the original systems. For-calculus, we further show that the yielded models are representationally complete, a desired property that is not enjoyed by many existing-calculus semantics. This work is part of a larger effort to develop a logical foundation for the programming language semantics framework K (http://kframework.org).