皮亚诺公理(Peano axioms)，也称皮亚诺公设，是意大利数学家皮亚诺提出的关于自然数的五条公理系统。根据这五条公理可以创建起一阶算术系统，也称皮亚诺算术系统。

皮亚诺的这五条公理用非形式化的方法叙述如下：

若将0也视作自然数，则公理中的1要换成0。

更正式的定义如下：

一个戴德金-皮亚诺结构为一满足下列条件的三元组（X, x, f）：

正式定义可以用谓词逻辑表示如下:

戴德金-皮亚诺结构可以描述为满足所有以下条件的三元组 (S, f, e)

In mathematical logic, the Peano axioms, also known as the Dedekind–Peano axioms or the Peano postulates, are a set of axioms for the natural numbers presented by the 19th century Italian mathematician Giuseppe Peano. These axioms have been used nearly unchanged in a number of metamathematical investigations, including research into fundamental questions of whether number theory is consistent and complete.