The words "who's" and "whose" are homophones, meaning they sound the same but are spelled differently and have different meanings. Because they sound alike, they are often confused. "Who's" is a contraction that can mean "who has" or "who is," while "whose" is the possessive of "who."

Using Who's

A good way to know when to use "who's" is remembering that it can only be used in a sentence when referring to people. In the sentence "Who's going to the party tonight?" the "who's" refers to the people going to the party. If "who is" or "who has" can be used in place of "who's" in the sentence, the word has been used correctly.

Using Whose

"Whose" differs from "who's" as it is a possessive term and can be used for both people and things. In the sentence "The man whose dog died is very sad," "whose" indicates that the dog belongs to the man. If "whose" can be replaced with "which" in the sentence or cannot be replaced with "who is" or "who has," the word has been used correctly.