代码混淆（Obfuscated code）亦称花指令，是将计算机进程的代码，转换成一种功能上等价，但是难于阅读和理解的形式的行为。代码混淆可以用于进程源代码，也可以用于进程编译而成的中间代码。执行代码混淆的进程被称作代码混淆器。目前已经存在许多种功能各异的代码混淆器。

代码混淆器也会带来一些问题。主要的问题包括：

Obfuscation is the obscuring of intended meaning in communication, making the message confusing, willfully ambiguous, or harder to understand. It may be intentional or unintentional (although the former is usually connoted) and may result from circumlocution (yielding wordiness) or from use of jargon or even argot (yielding economy of words but excluding outsiders from the communicative value). Unintended obfuscation in expository writing is usually a natural trait of early drafts in the writing process, when the composition is not yet advanced, and it can be improved with critical thinking and revising, either by the writer or by another person with sufficient reading comprehension and editing skills.