Who, whom, and related words like whoever and whomever are notorious for causing difficulties. How do you know when to use one or the other? Learning to recognize when the word is being used as a subject (who) and when it is being used as an object (whom) is the key to choosing the correct form.

First, let's look at the difference between a subject and an object. The subject is the one doing the action. The object receives the action. Consider the following sentence: The toddler bit the girl. The toddler did the biting. Toddler is the subject. The girl received the bite. Girl is the object.

Who is used when it is the subject of the sentence. Who bit the girl? Who is the subject. It stands for the one that bit the girl.

Whom is used when it is the object of the sentence. Whom did the toddler bite? Whom is the object. It stands in for the person receiving the bite.

Let's look at another sentence: Anthony visited his mother. Anthony did the visiting. Anthony is the subject. The mother received the visit. Mother is the object. If we ask questions about the visit, we would ask: Who visited his mother? Or Whom did Anthony visit? In the first question who stands in for Anthony, the one who did the visiting. In the second, whom stands in for mother, the one who received the visit.

An object of the preposition also takes objective case, so whom is the correct form when used as an object of the preposition. Beside whom did you sit at the banquet? To whom did you give the package? From whom is the letter? With whom was she speaking?

In all the examples above, who and whom were used as interrogative pronouns, pronouns used to ask a question. Things get a little trickier when who and whom are used as relative pronouns.

Relative pronouns introduce dependent clauses. A dependent clause has a subject and a verb but cannot stand on its own as an independent thought. Dependent clauses can function like three different parts of speech: adverb, adjective, or noun. A clause that functions as an adjective can be modifying a noun in the subjective case or the objective case. A clause acting as a noun can be used as a subject or object. The form of who/whom depends on the usage of the word within the clause, not on how the clause itself is used.

Here are some examples of clauses acting as the subject of a sentence. Whoever is going to the store should pick up a gallon of milk. In this sentence, whoever is going to the store is a dependent clause acting as the subject of the sentence. Whoever is the subject of the dependent clause.

The next sentence is a little different. Whomever you saw in the alley is likely to be the robber. The clause whomever you saw in the alley is the subject of the sentence, but whomever is the direct object of the clause.

Other times a clause acts as an object. It can be either the object of a verb or the object of a preposition. Again, it is the use of the who/whom within the clause that determines the correct form. The most common problem that arises is when who/whom follows a preposition. Sometimes whom is the object of the preposition. I talked to the man to whom you gave the brochure. In this sentence, to whom you gave the brochure is a dependent clause. You is the subject, brochure is the direct object, and whom is the object of the preposition to.

Sometimes a form of who/whom follows a preposition, but it is the whole clause that is the object of the preposition, not who/whom that is the object. Consider these two sentences: We gave the brochure to whoever came through the front door. We gave the brochure to whomever we saw. Whoever came through the front door and whomever we saw are noun clauses that act as objects of a preposition. In the first sentence, whoever is the subject of a clause; it stands for the ones coming through the door.

In the second sentence, whomever is the direct object in the clause; it stands for the ones who were seen, not the ones doing the seeing.

Whenever you are stuck on whether to use who or whom, ask yourself this question: Does who stand in the place of the one doing the action? If so, use who. If not, is it the one receiving the action, or is it an object of the preposition? If so, use whom.

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by Mary on 03.31.2018