Their vs. Theirs – Which is Correct?

“Their” is a possessive determiner used before a noun: “their house.” “Theirs” is a possessive pronoun used independently: “The house is theirs.” Both are correct, but they cannot usually replace each other. Use their to modify a noun and theirs to show ownership without repeating the noun. This distinction matters.

Their or Theirs – Which is Correct?

Their and theirs are both correct words, but they perform different grammatical functions. Their comes before a noun and identifies who owns or is associated with something: “Their decision surprised everyone.” Theirs stands alone and replaces a noun phrase: “The decision was theirs.”

This distinction is similar to the difference between my and mine, or your and yours. Because both words express possession, writers sometimes confuse them, especially when speaking quickly.

The Best Trick to Remember the Difference

Use the noun test: if a noun comes immediately after the word, choose their. If no noun follows because the ownership is already understood, choose theirs.

Compare these examples: “That is their car” and “That car is theirs.” You can also remember that theirs behaves like ours or yours: it normally appears without a following noun.

How to Use Their

Their is a possessive determiner, sometimes called a possessive adjective. It appears before a singular or plural noun to show that something belongs to, relates to, or is associated with two or more people. It can also refer to one person when the person’s gender is unknown, irrelevant, or when that person uses they pronouns.

Their is common in formal and casual English. It does not change according to the number of things owned. For example, both “their book” and “their books” use their.

Example 1: The students submitted their assignments before the deadline.

Example 2: Each applicant should attach their résumé.

Example 3: The company updated their privacy policy.

What are the different forms of their?

Their has no verb tenses, plural forms, or comparative and superlative degrees. It remains unchanged whether it modifies a singular noun, a plural noun, or a noun referring to one or more owners: “their plan,” “their plans,” “their child,” and “their children.”

The related possessive pronoun is theirs. The words their and theirs are not interchangeable when a noun follows. Write “their idea,” but “The idea is theirs.”

Etymology of the word their

Their developed from a possessive form of the Old Norse pronoun þeir, meaning “they.” It entered Middle English through contact between Old Norse and Old English speakers. Over time, it replaced earlier English possessive forms and became the standard third-person plural possessive determiner.

How to Use Theirs

Theirs is a possessive pronoun. It shows ownership without being followed by a noun because the relevant noun is understood from context. It often follows a linking verb such as is, was, or are, but it can also appear in other positions.

Theirs is appropriate in both formal and informal writing. It is especially useful for avoiding repetition: instead of writing “The blue bicycle belongs to them,” you can write “The blue bicycle is theirs.”

Example 1: We thought the umbrella was ours, but it was theirs.

Example 2: The responsibility for the final decision is theirs.

Example 3: Our seats are near the stage, while theirs are at the back.

What are the different forms of theirs?

Theirs does not have verb tenses, plural forms, or comparative and superlative degrees. It remains the same regardless of whether it refers to one item or several: “The choice is theirs” and “The supplies are theirs.”

Theirs normally stands alone and should not be placed directly before a noun in standard English. Use “their office,” not “theirs office.” Use “the office is theirs” when no noun follows the possessive pronoun.

Etymology of the word theirs

Theirs comes from the same historical possessive family as their. The ending developed to mark an independent possessive form, similar to ours, yours, and hers. Its role became distinct from their, which remained the form used before nouns.

Related Concepts

Understanding possessive determiners and possessive pronouns makes the difference between their and theirs much easier to recognize.

• Possessive determiners: Words such as my, your, his, her, our, and their come before nouns to identify ownership or association.
• Possessive pronouns: Words such as mine, yours, his, hers, ours, and theirs stand in place of noun phrases.
• Singular they: Their can refer to one person when that person uses they pronouns or when the person’s gender is unknown or not relevant.
• Subject-verb agreement: The noun after their determines the grammatical number of the noun phrase, while theirs itself can refer to either singular or plural possessions.

Examples from Media and Literature

Writers and speakers use their and theirs according to whether a noun follows. The following examples illustrate common real-world patterns:

• News writing: “The voters expressed their concerns” uses their before the noun concerns.
• Business communication: “The final decision is theirs” uses theirs independently to avoid repeating “the decision of the managers.”
• Children’s literature: Stories often describe characters returning to their homes, belongings, or families with their.
• Film dialogue: A character may say, “The choice is theirs,” using theirs to emphasize another person’s responsibility.
• Contemporary fiction: Authors frequently use singular their in sentences such as “Someone left their coat by the door,” when the person’s identity is unknown.

Practice Exercises

Choose the correct word to complete each sentence.

1. The neighbors invited us into _____ garden.
2. Those books belong to the researchers; they are _____.
3. Every employee must update _____ emergency contact details.
4. Our team finished early, but _____ needed another hour.
5. The decision to continue is _____.

Answer Key

1. their — It comes before the noun garden.
2. theirs — It stands alone and replaces “the researchers’ books.”
3. their — It comes before the noun phrase emergency contact details.
4. theirs — It stands alone and refers to the other team’s work.
5. theirs — It follows the linking verb and appears without a noun.

Their Synonyms

Theirs Synonyms

Frequently Asked Questions

Question 1: Is “their” or “theirs” correct?
Both are correct. Use their before a noun, as in “their car.” Use theirs without a following noun, as in “The car is theirs.”

Question 2: Can “theirs” be used before a noun?
No. In standard English, write “their house,” not “theirs house.” Use theirs when the noun is omitted: “The house is theirs.”

Question 3: Is “their” singular or plural?
Their can refer to multiple people, as in “The players changed their shoes,” or to one person in singular-they usage, as in “Someone forgot their keys.”

Question 4: What is the difference between “their” and “there”?
Their shows possession, while there refers to a place or introduces a statement. For example, “Their bags are over there.”

Question 5: What is the difference between “their” and “they’re”?
Their is possessive, while they’re is a contraction of “they are.” For example, “Their tickets are ready” differs from “They’re ready.”

Conclusion

Use their before a noun to show possession or association: “their plan.” Use theirs independently when the noun is understood: “The plan is theirs.” Both words are correct, but the noun test will help you choose accurately. Pro Tip: Correct possessive pronoun use strengthens clarity and protects your professional reputation.