Ever stared at a sentence and frozen because you weren't sure if that little curl on the 's' belonged there? It happens to the best of us. The confusion between both parties is a common grammatical error where writers incorrectly add an apostrophe to plural nouns that do not show possession. and party's is the possessive form of the singular noun party, indicating ownership by one specific group or individual. is one of those small details that can make your writing look sloppy, even if the rest of your content is sharp.

The good news? Once you understand the core logic, it becomes second nature. You don't need to memorize hundreds of exceptions. You just need to know what the word is doing in the sentence. Is it showing ownership? Or is it just counting things? That single question solves 90% of these issues instantly.

The Golden Rule: Ownership vs. Quantity

At its heart, English punctuation for these words comes down to two distinct jobs. First, we have the job of quantity. This is when you are simply saying how many groups are involved. Second, we have the job of ownership. This is when one of those groups owns something, like a decision, a mistake, or a responsibility.

When you are dealing with quantity, you use the plain plural form. No apostrophes allowed. When you are dealing with ownership, you use the possessive form. Apostrophes are the signal that says, "Hey, this belongs to someone." If nothing is being owned, the apostrophe has no reason to be there.

Think of it like a key. An apostrophe is a key that only opens the door of possession. If you try to use it on a door labeled "Counting," it won't work. It will just stick out awkwardly. So, before you type that apostrophe, ask yourself: "Does this group own something?" If the answer is no, leave the 's' alone.

Why "Both Parties" Has No Apostrophe

The phrase both parties refers to two distinct entities, groups, or individuals involved in a mutual agreement or conflict. is a standard plural construction. In English, most nouns form their plurals by simply adding an 's'. Because "party" ends in a consonant, we just tack on an 's' to make it "parties."

Many people get tripped up here because they hear "parties" and think, "Oh, it sounds like it needs an apostrophe because it's tricky." But sound isn't grammar. Spelling is. The word "parties" is just the plural version of "party." It functions exactly like "apples" is the plural of "apple" or "cities" is the plural of "city."

Consider these examples where both parties is used correctly without any punctuation marks:

• "Both parties agreed to the new terms." Here, you are just identifying who agreed. No one is owning the agreement; they are participating in it.

• "The lawyer spoke to both parties separately." Again, simple identification. The lawyer is talking to them. He doesn't own them.

• "It was a dispute between both parties over the contract." The dispute exists between them. They aren't owning the dispute in a way that requires possessive grammar; they are the participants.

If you see "both party's" in a document, it is almost certainly wrong. Unless you are talking about two separate events (like a birthday party and a retirement party) where each event owns something specific, the plural "parties" is the correct choice for groups of people or organizations.

When to Use "Party's" Correctly

Now, let's flip the script. When does the apostrophe actually earn its keep? You use party's when a single entity holds ownership or responsibility for a specific object, action, or concept. This is the singular possessive form.

This usually happens when you are focusing on one specific group rather than the pair as a whole. For example, if you are discussing the obligations of just one side in a negotiation, you might refer to that specific side's duties.

Here is how party's looks in practice:

• "The party's response was delayed by three days." Who responded? One specific party. The response belongs to that party.

• "We need to review the party's financial records." Whose records? The records belong to the party.

• "Each party's signature is required." Even though there are two parties total, we are looking at the signature belonging to *each* individual party separately.

Notice the shift in focus. In the first set of examples, we were looking at the duo together. In this set, we are zooming in on the individual owner. That zoom-in is what triggers the apostrophe.

Common Pitfalls and How to Avoid Them

Even native speakers mess this up. Why? Because English spelling can feel arbitrary. But for this specific rule, the logic is tight. Here are the most common traps and how to dodge them.

Pitfall 1: Confusing Plural with Possessive This is the big one. People see a plural word and instinctively add an apostrophe because they've seen it done with other words (like "children's"). But "parties" is already plural. Adding an apostrophe makes it possessive, which changes the meaning entirely. If you mean more than one, stop. Don't add the mark.

Pitfall 2: The "Joint Ownership" Trap What if both parties own something together? Like, "Both parties' signatures are needed." Wait, did I just use an apostrophe after the s? Yes. When multiple owners share something jointly, the apostrophe goes after the final 's.' So, "parties'" indicates joint ownership. But if you are talking about them individually, you use "party's" for each one. Context is king here.

Pitfall 3: Overthinking the Sound Don't write what you hear. Write what the grammar demands. "Parties" sounds like it has a hidden 't', but it doesn't. And it definitely doesn't sound like an apostrophe. Trust the rule, not your ear.

A Quick Comparison Table

To make this crystal clear, let's lay out the differences side-by-side. This table serves as a cheat sheet for your next draft.

Keep this table handy. When in doubt, check the function. Is it counting? Use the plain plural. Is it owning? Use the possessive.

Practical Tips for Writers

How do you internalize this so you stop second-guessing yourself? Here are a few practical strategies that help build muscle memory.

1. Substitute a Simpler Word. Try swapping "party" with "person" or "group." Does it make sense? "Both persons agreed." Yes. "Person's response." Yes. If the substitution works, your original structure is likely correct. If you tried "both person's," it would sound wrong immediately, reminding you that the plural doesn't take an apostrophe.

2. Look for the Object. Ask, "What does the party own?" If there is no object following the word that belongs to the party, you probably don't need the apostrophe. If there is an object (like "decision," "email," or "signature"), check if it belongs to one party or both.

3. Read It Aloud Slowly. While sound isn't the primary guide, rhythm can help. "Both parties" flows as a unit. "Party's" has a distinct pause or emphasis on the possessive nature. If the sentence feels rushed and factual, it's likely a count. If it feels personal or attributive, it's likely possession.

Also, remember that context matters. In legal documents, precision is everything. A misplaced apostrophe can technically change the liability of a clause. In casual emails, people might forgive it, but in professional writing, accuracy builds trust. Your readers want to know you know what you're doing.

Frequently Asked Questions