Themselves and theirselves are plural pronouns used reflexively and considered as acceptable variations. They are used as a reflexive pronoun form when referring to a group of people, animals, or things in the third person point of view when: (1) used as an object of a verb or preposition; (2) emphasizing the pronoun “they” or a plural noun; and (3) emphasizing an indefinite gender-neutral pronoun being referred to and replacing himself/herself.
Remember, the difference between the two is themselves is correct and standard while theirselves is nonstandard. Therefore, always use themselves instead of theirselves.
(Note: a reflexive pronoun refers back to a person or thing being referred to in a sentence. Use reflexive pronouns when a verb or preposition’s subject or object are the same.)
When to Use Themselves
Themselves is the correct and standard reflexive pronoun form of “they.” We use themselves in three ways.
First, it refers to an object of a verb or preposition when the verb’s subject is “they” or a group of people. Second, it emphasizes the pronoun “they” or a plural noun. Lastly, it emphasizes an indefinite gender-neutral pronoun being referred to (whether the gender is unknown, unsure, or unimportant in the context.)
Furthermore, themselves replaces himself or herself in a sentence.
Themselves is Standard
Referring to an Object of a Verb or Preposition
Ronald and his best friends are enjoying themselves on a Saturday boys’ night out.
(Explanation: enjoying is the verb, and themselves is the object of the verb “enjoying.”)
The kids seem very pleased with themselves after crossing a border.
(Explanation: with is the preposition and themselves is the object of the preposition “with.”)
The band members have ingrained parts of themselves that are irreplaceable.
Those girls talked amongst themselves while having wine and steak.
When to Use Theirselves
Theirselves is the nonstandard reflexive pronoun form of “they” and is used the same way as themselves. It’s highly recommended that we avoid using theirselves and use themselves instead. Also, theirselves is rarely used in spoken English and extremely rare in written English. Hence, always use themselves.
Theirselves is Nonstandard
They saw theirselves laughing at their silly mistakes.
They saw themselves laughing at their silly mistakes.
The dogs theirselves approached me first.
The dogs themselves approached me first.
No one should blame theirselves for the unexpected misfortune.
No one should blame themselves for the unexpected misfortune.
Conclusion: Themselves vs. Theirselves: Which One is Correct?
Between themselves and theirselves, the correct variation is themselves while theirselves is nonstandard. Remember, always use themselves instead of theirselves.
Cambridge Dictionary. (n.d.) Themselves. In https://dictionary.cambridge.org/us/ dictionary. Retrieved from https://dictionary.cambridge.org/us/dictionary/english/themselves
Collins Dictionary. (n.d.) Themselves. In https://www.collinsdictionary.com/ dictionary. Retrieved from https://www.collinsdictionary.com/dictionary/english/themselves
Longman Dictionary of Contemporary English Online. (n.d.). Themselves. In https://www.ldoceonline.com/ dictionary. Retrieved from https://www.ldoceonline.com/dictionary/themselves
Merriam-Webster. (n.d.). Themselves. In Merriam-Webster.com dictionary. Retrieved from https://www.merriam-webster.com/dictionary/themselves