“Some of whom” is the correct phrase. “Some of who” is grammatically incorrect in standard English.
The preposition “of” requires an object pronoun — and whom is the object pronoun, while who is the subject pronoun. This single rule resolves the confusion completely.
This guide explains why “some of whom” is always correct, how the who vs whom rule works, and how to apply it confidently every time.
The Quick Answer
“Some of whom” ✅ — always correct “Some of who” ❌ — always incorrect in formal and standard writing
Example: “I invited ten colleagues, some of whom I had never met before.”
Here, whom follows the preposition of — and prepositions always require object pronouns. Whom is an object pronoun. Who is a subject pronoun. The rule is that simple.
Why “Some of Whom” Is Correct — The Preposition Rule
The entire explanation comes down to one grammatical rule:
Prepositions require object pronouns — not subject pronouns.
Look at how this works with personal pronouns:
The same principle applies to who and whom:
- Whom = object pronoun (equivalent to him/her/them)
- Who = subject pronoun (equivalent to he/she/they)
Since “of” is a preposition — it must be followed by whom, not who.
“Some of whom” = “some of them” ✅ “Some of who” = “some of they” ❌ — obviously wrong
The Him/Her Test — The Fastest Way to Check
The most reliable trick for choosing between who and whom:
Substitute him/her/them or he/she/they into the sentence.
- If him/her/them fits → use whom
- If he/she/they fits → use who
Applied to this phrase:
“I met many people, some of ___ I recognized.” → “Some of them I recognized.” ✅ → him/them fits → use whom → “Some of they I recognized.” ❌ → he/they does not fit
Result: “some of whom I recognized” ✅
More Examples: “Of Whom” vs “Of Them”
Who vs Whom — The Core Difference
When to Use Whom and When to Use Who

When to Use Who
Use who when it is the subject of a clause — the one performing the action:
- “I invited friends who enjoy music.” (They enjoy music ✅)
- “She is the one who called.” (She called ✅)
- “The people who attended were impressed.” (They attended ✅)
When to Use Whom
Use whom when it is the object of a verb or preposition — the one receiving the action:
- “I invited friends, some of whom brought dessert.” (Some of them brought dessert ✅)
- “To whom did you send the email?” (You sent it to him ✅)
- “She is someone with whom I work closely.” (I work with her ✅)
“Some of Whom” in Different Sentence Structures
“Some of whom” is a relative clause connector — it links back to a group of people just mentioned and introduces additional information about some of them.
Common patterns:
Group + “Of Whom” Structures
All of these use whom — because in every case, the pronoun follows a preposition (of).
Common Mistakes to Avoid
Is “Some of Who” Ever Acceptable?
In very casual speech, some people say “some of who” — and while it may be understood, it is never considered grammatically correct in any formal, academic, or professional writing context.
There is no writing situation where “some of who” is the preferred or recommended choice. “Some of whom” is always correct — in every register.
FAQs — Some of Whom or Some of Who
Is it some of whom or some of who?
“Some of whom” is always correct. The preposition of requires the object pronoun whom — not the subject pronoun who. Apply the him/them test: “some of them” works, “some of they” does not — so use whom.
Is it 70-year-old or 70 years old?
When used before a noun as a compound modifier — use hyphens: “a 70-year-old man.” When used after a noun as a description — no hyphens: “He is 70 years old.” The position in the sentence determines whether hyphens are needed.
How do I use whom correctly?
Use whom whenever the pronoun is the object of a verb or preposition. Apply the him/her test: if him or them fits the sentence naturally — use whom. Example: “To whom did you speak?” = “You spoke to him.” ✅
Why do people say whom instead of who?
People use whom to follow formal grammar rules that distinguish subject pronouns (who, he, she, they) from object pronouns (whom, him, her, them). After prepositions like of, to, with, by — whom is always the grammatically required form.
Conclusion
The rule is clear and consistent. “Some of whom” is always correct because the preposition of requires an object pronoun — and whom is the object pronoun. “Some of who” treats who as if it were an object pronoun, which it never is.
Use the him/them test every time you are unsure — if them fits, write whom. Apply that check once and “some of whom” will always be your natural, confident choice in any piece of writing.

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