Quick answer: Who's (with an apostrophe) is a contraction of "who is" or "who has": Who's coming to the party? Whose (no apostrophe) is a possessive determiner or pronoun meaning "belonging to whom": Whose bag is this? Memory trick: if you can expand the word into "who is" or "who has," you need the apostrophe (who's); if you're asking about ownership, drop the apostrophe (whose). For a fuller definition, see the Cambridge Dictionary entry for ‘who's’.
Comparison Table
| Word | Part of Speech | Meaning | Example |
|---|---|---|---|
| who's | contraction | short for "who is" or "who has" | Who's taken my pen? |
| whose | possessive determiner / pronoun | belonging to whom; used to ask or state ownership | Whose car is parked outside? |
Using Who's (Contraction)
Who's is a contraction that combines "who" with either "is" or "has." The apostrophe signals that a letter or letters have been removed, exactly as in other contractions like "it's" (it is/has) or "she's" (she is/has). To check whether "who's" is correct, try expanding it back to "who is" or "who has" — if the sentence still makes sense, the apostrophe belongs there.
Who's coming to the party this weekend?
Who's taken my umbrella? (= who has taken)
Do you know who's responsible for this decision?
Who's going to answer the phone?
I wonder who's been eating my sandwich.
The Expansion Test
- "Who's at the door?" → "Who is at the door?" ✓
- "Who's seen my keys?" → "Who has seen my keys?" ✓
- If neither expansion works, you need whose, not who's.
Using Whose (Possessive)
Whose is a possessive determiner and pronoun used to ask about or refer to ownership — it means "belonging to whom" or "of whom." As covered in this guide to English possessives, whose functions much like "his," "her," or "their" but is specifically used in questions and relative clauses about people (and sometimes things).
Whose bag is this on the table?
I met the woman whose car was stolen last week.
Whose idea was it to leave early?
The company whose logo appears on the packaging is based in Berlin.
Do you know whose turn it is to cook dinner?
Whose as a Relative Pronoun
Whose is frequently used to introduce relative clauses that show possession, connecting a noun to something it owns or is associated with: "the man whose dog barked all night"; "a company whose profits doubled last year." This use works for both people and, less commonly but still correctly, for things and organisations.
Memory Trick
This pair follows the exact same pattern as it's (it is/has) versus its (possessive) — a very common source of confusion in English precisely because possessive forms usually take an apostrophe (as in "Sarah's book"), but possessive pronouns and determiners like "its," "whose," "his," "hers," and "theirs" never do. Remember the rule: no apostrophe for possession in these special words. If you can substitute "who is" or "who has," add the apostrophe; otherwise, leave it out.
Common Mistakes
✗ Who's bag is this?
✓ Whose bag is this?
✗ Whose coming to the meeting?
✓ Who's coming to the meeting?
✗ I met the man who's car was stolen.
✓ I met the man whose car was stolen.
✗ I don't know who's turn it is.
✓ I don't know whose turn it is.
Quick Check: Who's or Whose?
Four questions — choose the correct word for each sentence.
1. “___ coming to the party?”
2. “___ bag is this on the table?”
3. “I met the man ___ car was stolen.”
4. “___ seen my keys?” (= who has seen)
Frequently Asked Questions
What is the difference between who's and whose?
Who's (with an apostrophe) is a contraction meaning "who is" or "who has": "Who's coming to the party?" Whose (without an apostrophe) is a possessive determiner or pronoun meaning "belonging to whom": "Whose bag is this?" The two words sound identical, but the apostrophe signals a contraction, not possession — a pattern that also applies to "it's" versus "its."
How can I check which word I need?
Try expanding "who's" back into "who is" or "who has." If the sentence still makes sense, "who's" (with the apostrophe) is correct: "Who's at the door?" → "Who is at the door?" — works. If expanding it doesn't make sense, and you're actually asking about ownership, use "whose" instead: "Whose car is this?" cannot become "Who is car is this," so "whose" is required.
Why doesn't "whose" have an apostrophe if it shows possession?
Most nouns show possession with an apostrophe plus "s" (Sarah's book), but possessive pronouns and determiners in English — including "his," "hers," "its," "theirs," "yours," and "whose" — never take an apostrophe. This is a consistent grammar rule, even though it can feel surprising to learners, since apostrophes are so strongly associated with possession elsewhere.
Can "whose" refer to things, not just people?
Yes. While "whose" most often refers to people ("the woman whose car was stolen"), it can also refer to organisations, objects, or abstract things in more formal writing: "the company whose profits doubled," "a country whose history is complex." Some style guides prefer "of which" for things in very formal contexts, but "whose" is widely accepted and commonly used.
Is "who's" ever correct in formal writing?
Yes, "who's" is a standard contraction and is grammatically correct in both formal and informal writing, though some very formal or academic styles prefer to avoid contractions altogether and would write "who is" or "who has" in full. There is nothing inherently informal or incorrect about "who's" itself — the confusion is purely about spelling it correctly versus "whose."
Is this confusion common among native English speakers?
Yes, extremely common — mixing up who's and whose is one of the most frequent spelling errors made by native English speakers, not just learners, largely because the words are pronounced identically. It falls into the same category of error as confusing "its/it's" and "your/you're," where an apostrophe silently changes a word's grammatical function without changing its sound.
What does "who's who" mean?
"Who's who" is an idiomatic phrase meaning the important or well-known people in a particular field or group, often used as the title of reference books listing notable individuals: "The gala was a who's who of the fashion industry." It always uses "who's" (who is), never "whose," since it is built from the contraction, not the possessive form.
Can "whose" be used in indirect questions?
Yes. "Whose" frequently introduces indirect questions about ownership: "I don't know whose turn it is"; "She asked whose idea it was." In these constructions, "whose" functions as an interrogative determiner within the embedded question, and it never takes an apostrophe, regardless of how the surrounding sentence is structured.
Does "who's" ever mean "who has" instead of "who is"?
Yes, "who's" can expand to either "who is" or "who has," depending on context: "Who's got the keys?" means "Who has got the keys?" while "Who's at the door?" means "Who is at the door?" Both expansions are correct uses of the same contraction, and neither relates to whose (possession).
How can I remember the difference for good?
Compare who's/whose directly to it's/its: an apostrophe always signals a shortened form (it is, who is), never possession, for these particular pronoun-based words. A simple test sentence to memorise: "Who's got a friend whose dog barks all night?" — the first "who's" expands to "who has," and the second "whose" shows possession (the dog belongs to the friend).