“Coworker” and “co-worker” are both correct. They mean the same thing: a person you work with. The only spelling that is wrong is “co worker” with a space in the middle.
People search for “coworker vs co worker” because all three forms show up in emails, job posts, and news stories. This article explains which form to choose and why.
The short answer
- Coworker (one word) is the standard choice in American English.
- Co-worker (with a hyphen) is also correct and is still common, especially in British English.
- Co worker (two words) is a mistake.
Pick one spelling and use it everywhere in the same document.
What the word means
A coworker is someone who works with you, usually at the same company or in the same workplace. They may be on your team, or just in the same office.
- My coworker covered my shift on Friday.
- She gets along well with her co-workers.
- I have lunch with a coworker every Tuesday.
Why there are two spellings
The prefix “co-” means “together” or “joint.” English has long debated whether to attach it directly to the next word or add a hyphen. The hyphen helped readers when two vowels met, as in “co-operate” and “co-worker.” Over time, many words lost the hyphen. “Cooperate” is now the normal spelling, and “coworker” has followed the same path in American writing.
Neither form is a typo. Dictionaries and style guides simply prefer different ones.
Which one should you use?
For American readers, use “coworker.” Merriam-Webster lists it as the main spelling, and the AP Stylebook uses it too.
For British, Australian, or other international readers, “co-worker” is a safe choice. Many UK dictionaries and publishers still show the hyphenated form.
If you follow a style guide, follow it. Your company, school, or publication may already have a rule. If it does, that rule wins.
If you have no guide, choose one and stay consistent. Switching between “coworker” and “co-worker” in the same piece looks careless.
| Form | Status | Where you’ll see it |
| coworker | Correct | Mostly American English |
| co-worker | Correct | Common in British English and many other publications |
| co worker | Incorrect | Not an accepted spelling |
Why “co worker” is wrong
With a space, “co worker” looks like two separate words. But “co” is not a word by itself here. It is a prefix, and a prefix has to attach to the word it changes, either directly or with a hyphen.
- Wrong: She is my co worker.
- Right: She is my coworker.
- Right: She is my co-worker.
Plural and possessive forms
The same spelling rule applies to every form of the word.
- Plural: coworkers or co-workers
- Singular possessive: my coworker’s desk (my co-worker’s desk)
- Plural possessive: my coworkers’ lunch orders (my co-workers’ lunch orders)
Add the apostrophe after the “s” when more than one person owns the thing.
Related words that confuse people
“Coworking” (as in a coworking space) is usually written as one word, though you will sometimes see “co-working.” Words like “colleague,” “teammate,” and “peer” are related, but they are separate words with their own meanings. “Colleague” often suggests someone in the same profession or organization, while “coworker” simply means someone you work alongside.
Quick takeaway
Write “coworker” for American audiences and “co-worker” if your style guide or readers prefer the hyphen. Avoid “co worker” with a space. Whichever correct form you choose, use it the same way throughout.
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I write clear, practical English lessons for everyday use. On Lingotexting, I break down grammar, vocabulary, and word types into simple ideas you can apply quickly. My focus is accuracy, real examples, and helpful visuals, so learners build confidence, improve writing, and communicate naturally in school, work, and daily life.