衍生物（derivative）指一种简单化合物中的氢原子或原子团被其他原子或原子团取代而衍生的较复杂的产物。例如，以甲烷（CH₄）为母体，则甲醇（CH₃OH）、甲酸（HCOOH）、一氯甲烷（CH₃Cl）等均为甲烷的衍生物。

In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction.

In the past, derivative also meant a compound that can be imagined to arise from another compound, if one atom or group of atoms is replaced with another atom or group of atoms, but modern chemical language now uses the term structural analog for this meaning, thus eliminating ambiguity. The term "structural analogue" is common in organic chemistry.