保序回归（英文：Isotonic regression）在数值分析中指的是在保序约束下搜索一个加权 w 的最小二乘 y 以拟合变量 x，它是一个二次规划问题：

subject to

(这个条件有错误）

保序回归应用于统计推理、多维标度等研究中。

In numerical analysis, isotonic regression (IR) involves finding a weighted least-squares fit to a vector with weights vector subject to a set of non-contradictory constraints of the kind .

Such constraints define partial order or total order and can be represented as a directed graph , where N is the set of variables involved, and E is the set of pairs (i, j) for each constraint . Thus, the IR problem corresponds to the following quadratic program (QP):