伪代码（英语：pseudocode），又称为虚拟代码，是高层次描述算法的一种方法。它不是一种现实存在的编程语言（已经出现了类似伪代码的语言，参见Nuva）；它可能综合使用多种编程语言的语法、保留字，甚至会用到自然语言。

它以编程语言的书写形式指明算法的职能。相比于进程语言（例如Java、C++、C、Delphi 等等）它更类似自然语言。它是半角式化、不标准的语言。我们可以将整个算法运行过程的结构用接近自然语言的形式（这里可以使用任何一种作者熟悉的文本，例如中文、英文，重点是将进程的意思表达出来）描述出来。使用伪代码，可以帮助我们更好的表述算法，不用拘泥于具体的实现。

Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm.

It uses the structural conventions of a normal programming language, but is intended for human reading rather than machine reading. Pseudocode typically omits details that are essential for machine understanding of the algorithm, such as variable declarations, system-specific code and some subroutines. The programming language is augmented with natural language description details, where convenient, or with compact mathematical notation. The purpose of using pseudocode is that it is easier for people to understand than conventional programming language code, and that it is an efficient and environment-independent description of the key principles of an algorithm. It is commonly used in textbooks and scientific publications that are documenting various algorithms, and also in planning of computer program development, for sketching out the structure of the program before the actual coding takes place.