The plural of "mouse" is "mice". This is an example of an irregular plural noun, which means that it does not follow the standard rule of adding "-s" or "-es" to the end of the word to make it plural. Instead, the word "mouse" changes to "mice" when referring to more than one of them. It is worth noting that the plural of "computer mouse" can be either "computer mice" or "computer mouses," but "computer mice" is more commonly used.