This tragic error is similar to the its and it’s problem, and luckily for you, the solution is just as simple. Pay attention to the apostrophe and you’ll know which one to choose.
- Whose on first?
- I can’t even tell whose there because the lights are too low.
- Who’s crab cakes were left in the fridge over the weekend?
Both whose and who’s have at their root the pronoun who. Whether you intend to say whose or who’s is irrelevant when you speak because they sound the same. However, they must be distinct from one another in writing. As with its and your (two other possessive pronouns), whose never takes an apostrophe. By contrast, who’s always takes an apostrophe to show that it is a contraction of who is.
Would the sentence make sense with who is? If so, use that contraction! “He’s the man who’s responsible for throwing a neighborhood party.” If not, you’ll need whose: “He’s the man whose dog ate all the hors d’oeuvres.”