brother-in-laws (brothers-in-law)

Quick answer

No - "in_laws" is incorrect. Use a hyphen for the family term: "in-law" (singular) and "in-laws" (plural for the group). For compound relatives like "brother-in-law," form the plural by making the head noun plural: "brothers-in-law."

Core explanation: hyphens, spacing, and plural rules

English has three basic compound forms: closed (no space), hyphenated, and open (two words). Relatives formed with in (in-law, son-in-law, sister-in-law) are hyphenated. When you make them plural, change the main noun, not the in- part.

• Singular: sister-in-law
• Plural: sisters-in-law
• Shorthand group: in-laws (refers to parents/relatives by marriage)

Writing "in laws" (two words) looks like an open compound and can be misread. "in_laws" (with an underscore) is a formatting artifact, not standard text.

Hyphenation vs spacing: when to hyphenate

Hyphens join words that form a single idea or modify another word. Use them for fixed family terms and when the compound acts as a modifier:

• Correct: my mother-in-law
• Correct as modifier: an in-law visit (hyphen keeps the phrase tight)
• Avoid: in laws (this reads as two separate words and creates ambiguity)

Real usage: work, school, and casual examples

Here are natural sentences showing the correct hyphenated forms in different settings.

• Work: My in-laws will help with the move this weekend.
• Work: We scheduled an in-law visit as part of the relocation plan.
• Work: Please note the expense for my sister-in-law's travel.
• School: The student's parent-in-law attended the conference.
• School: Bring a note if an in-law will pick up your child.
• School: The group included two brothers-in-law from the same family.
• Casual: My in-laws are coming over for dinner.
• Casual: I swapped stories with a cousin-in-law at the barbecue.
• Casual: The brothers-in-law decided to take a fishing trip.

Wrong vs right examples you can copy

Six quick pairs that show the typical mistakes and the correct forms.

• Wrong: I spoke to my in laws yesterday.
  Right: I spoke to my in-laws yesterday.
• Wrong: The task affects the sister in law schedule.
  Right: The task affects the sister-in-law's schedule.
• Wrong: He is one of the brother-in-laws.
  Right: He is one of the brothers-in-law.
• Wrong: We'll invite the parent in law next week.
  Right: We'll invite the parent-in-law next week.
• Wrong: Her in laws love gardening.
  Right: Her in-laws love gardening.
• Wrong: The son in law arrived late.
  Right: The son-in-law arrived late.

How to fix your sentence: quick rewrite steps

Fixing these errors is about identifying the compound and pluralizing the head word when needed.

1. Find the full compound (e.g., "sister-in-law").
2. Hyphenate the parts: in-law.
3. If plural, make the main noun plural: sisters-in-law.
4. Read the full sentence aloud to ensure it sounds natural; adjust if the compound functions as an adjective.

Three practical rewrites:

• Original: My in laws arrive Monday.
  Rewrite: My in-laws arrive Monday.
• Original: The brother in law meetings are monthly.
  Rewrite: The brothers-in-law meetings are monthly. (Better: Meetings of the brothers-in-law are monthly.)
• Original: Is that parent in law coming?
  Rewrite: Is that parent-in-law coming?

A simple memory trick

Think of the hyphen as a glue linking the phrase parts. For plurals, picture which word does the owning or doing - that's the one you pluralize. Example: brother-in-law = brothers-in-law.

• Hyphen = glue
• Pluralize the head noun (brother, son, sister)
• Use "in-laws" as a group shorthand

Similar mistakes to watch for

Spacing and hyphenation errors often appear together. Scan your text for related patterns.

• Open vs. hyphenated compounds (e.g., "middle aged" vs. "middle-aged")
• Plural placement in multiword nouns (e.g., "passerby" → "passersby")
• Apostrophe confusion in possessives of compound nouns
• Underscores or accidental spaces introduced by formatting tools

FAQ

Is "in laws" ever correct?

Not for the family term. "In laws" as two words could appear by mistake or if the context truly needs "in" + "laws" with separate meanings (for example, "in laws" in a sentence like "We discussed laws in 2020"), but as a relative term it should be "in-law" or "in-laws."

How do I form the plural of brother-in-law?

Make the main noun plural: brothers-in-law.

Should I hyphenate when the phrase comes before a noun?

Yes-when the compound functions as a single adjective before a noun, keep the hyphen to avoid ambiguity: an in-law visit, a sister-in-law relationship.

What about using "in-laws" as shorthand?

"In-laws" is standard shorthand for a spouse's family (the in-law relatives). It's fine in formal and informal writing when you mean the group.

Can spellcheck catch these errors?

Sometimes, but not always. Spellcheck can miss missing hyphens or incorrect plural placement, so read the sentence for meaning and structure.

Final tip: check the whole sentence before you send it

Fix the compound, hyphenate correctly, pluralize the head noun, and then read the sentence once more for clarity. Batch-fix repeated mistakes across your document to save time.