在数学和统计学里，参数（英语：parameter）是使用通用变量来创建函数和变量之间关系（当这种关系很难用方程来阐述时）的一个数量。在不同的语境里这一术语可能有特殊用途。

A parameter (from the Ancient Greek παρά, "para", meaning "beside, subsidiary" and μέτρον, "metron", meaning "measure"), in its common meaning, is a characteristic, feature, or measurable factor that can help in defining a particular system. A parameter is an important element to consider in evaluation or comprehension of an event, project, or situation. Parameter has more specific interpretations in mathematics, logic, linguistics, environmental science, and other disciplines.