在面向对象的进程设计中，里氏替换原则（Liskov Substitution principle）是对子类型的特别定义。它由芭芭拉·利斯科夫（Barbara Liskov）在1987年在一次会议上名为“数据的抽象与层次”的演说中首先提出。

里氏替换原则的内容可以描述为： “派生类（子类）对象能够替换其基类（超类）对象被使用。” 以上内容并非利斯科夫的原文，而是译自罗伯特·马丁（Robert Martin）对原文的解读。其原文为：

芭芭拉·利斯科夫与周以真（Jeannette Wing）在1994年发表论文并提出的以上的Liskov代换原则。

Substitutability is a principle in object-oriented programming. It states that, in a computer program, if S is a subtype of T, then objects of type T may be replaced with objects of type S (i.e. objects of type S may substitute objects of type T) without altering any of the desirable properties of that program (correctness, task performed, etc.). More formally, the Liskov substitution principle (LSP) is a particular definition of a subtyping relation, called (strong) behavioral subtyping, that was initially introduced by Barbara Liskov in a 1987 conference keynote address entitled Data abstraction and hierarchy. It is a semantic rather than merely syntactic relation because it intends to guarantee semantic interoperability of types in a hierarchy, object types in particular. Barbara Liskov and Jeannette Wing formulated the principle succinctly in a 1994 paper as follows: