This paper studies the differential lattice, defined to be a lattice L equipped with a map d : L → L that satisfies a lattice analog of the Leibniz rule for a derivation. Isomorphic differential lattices are studied and classifications of differential lattices are obtained for some basic lattices. Several families of derivations on a lattice are explicitly constructed, giving realizations of the lattice as lattices of derivations. Derivations on a finite distributive lattice are shown to have a natural structure of lattice. Moreover, derivations on a complete infinitely distributive lattice form a complete lattice. For a general lattice, it is conjectured that its poset of derivations is a lattice that uniquely determines the given lattice. Contents 1. Introduction 1 2. Differential lattices and basic properties 3 3. Isomorphic classes of differential lattices 6 3.1. Isomorphic differential lattices 6 3.2. Classification of differential lattices 9 4. The lattices of derivations 13 4.1. Lattice structures for derivations on distributive lattices 13 4.2. Lattice structures on inner and other special derivations 16 4.3. Lattice structures for derivations on specific lattices 18 References 21