辅音变化（consonant mutation、音变）在语言学里是指一个字的辅音根据其本身字词的语形及前后的语法发生变化的现象。一般所称之「音变」大抵指的是「辅音的变化」。辅音变化的现象在世界上的许多语言里都能发现，然而最典型，也最为代表性的辅音变化，是现今所有凯尔特语族语言的前缀辅音变化。前缀辅音变化的现象也可在日语、印度语、马来语、南派优印地安语、及许多西非的语言（例如富拉语）中发现。芬兰语支的语言如芬兰语和爱沙尼亚语有字中辅音变化；肯尼亚地区尼罗-撒哈拉语系的卢奥语和英语有词干后缀的辅音变化。而希伯来语则在前缀、字中、后缀全具有辅音变化。

Consonant mutation is change in a consonant in a word according to its morphological or syntactic environment.

Mutation phenomena occur in languages around the world. A prototypical example of consonant mutation is the initial consonant mutation of all modern Celtic languages. Initial consonant mutation is also found in Indonesian or Malay, in Southern Paiute and in several West African languages such as Fula. The Nilotic language Dholuo, spoken in Kenya, shows mutation of stem-final consonants, as does English to a small extent. Mutation of initial, medial, and final consonants is found in Modern Hebrew. Japanese exhibits word medial consonant mutation involving voicing, rendaku, in many compounds.