You typed “on this matter” into an email, then second-guessed yourself and changed it to “in this matter.” Then you changed it back. Sound familiar? This tiny two-word swap trips up even experienced writers, and picking the wrong one in a legal brief or client email can make your writing look sloppy or confused.
The good news is the rule is simpler than it feels once you see it laid out clearly. This guide settles the on this matter vs in this matter debate for good, with rules you can actually remember.
Understanding the Core Difference
The words “on” and “in” seem interchangeable at a glance, but they carry different shades of meaning in English. “On” points to a surface or topic, the thing you are addressing from the outside. “In” points to something you are inside of, involved with, or bound to.
That distinction is exactly why the on this matter vs in this matter question keeps coming up. Once you treat “matter” as either a topic (on) or a case (in), the fog clears fast.
What Does “On This Matter” Mean?
“On this matter” means “regarding this topic” or “about this subject.” You use it when offering an opinion, giving feedback, or discussing something in a general sense. It works in meetings, emails, articles, and everyday conversation.
For example: “I’d like to share my thoughts on this matter before we vote.” Here, the speaker is commenting on a topic, not acting inside a formal proceeding.
What Does “In This Matter” Mean?
“In this matter” means “in this case” or “in this specific proceeding.” It shows up almost exclusively in legal, official, or highly formal writing where a defined case or file is being referenced.
For example: “The court has not yet ruled in this matter.” Here, “matter” refers to an actual case or file, something with a docket number and defined parties, not a loose topic of conversation.
Quick Comparison Table
| Feature | On This Matter | In This Matter |
| Meaning | About this topic | Within this case or proceeding |
| Common Setting | Business, everyday, editorial | Legal, judicial, official documents |
| Formality Level | Neutral to formal | Highly formal |
| Grammatical Role | Prepositional phrase (topic) | Prepositional phrase (involvement) |
| Typical Users | Managers, writers, general public | Lawyers, judges, HR officers |
| Style Guide Notes | No hyphen required | No hyphen required |
Detailed Usage Rules
Getting the on this matter vs in this matter choice right comes down to three simple checks. Ask yourself whether you are commenting, deciding, or already involved in something official.
Use “on this matter” when discussing or commenting. If you are sharing an opinion, giving advice, or referencing a general subject, “on” is correct. It signals distance, you are talking about the topic from outside it.
Use “in this matter” for formal or legal contexts. If you are referring to an active case, dispute, or official proceeding where you or someone else holds a defined role, “in” is correct. It signals involvement, you are inside the situation.
Avoid mixing them inappropriately. Swapping “in” for “on” in casual writing can sound stiff or overly legalistic. Swapping “on” for “in” in a legal document can sound imprecise and undercut your credibility. Match the phrase to the register of your writing.
Compound Noun and Grammar Notes
“Matter” here functions as an abstract noun, not a compound noun, so no hyphen is needed in either phrase. Writers sometimes second-guess this because English hyphenates many two-word modifiers, but “on this matter” and “in this matter” are standard prepositional phrases, not compound adjectives.
Neither the Chicago Manual of Style nor APA style calls for a hyphen in either construction, since hyphens are reserved for compound modifiers directly before a noun, not for prepositional phrases like these.
Practical Examples in Different Contexts
Business Communication
In a business setting, “on this matter” is the natural choice for everyday correspondence. Example: “Please let us know your position on this matter by Friday.” Example:
“We appreciate your patience on this matter while we review the contract.” Business writing rarely needs “in this matter” unless HR or legal teams are handling a formal complaint or investigation.
Legal or Formal Writing
Legal writing leans heavily on “in this matter.” Example: “The plaintiff has filed a motion in this matter.” Example: “Counsel for both parties agreed to a hearing date in this matter.” You will also see it in HR investigations: “The company will remain neutral in this matter until the internal review concludes.”
Everyday English
In casual conversation, “on this matter” dominates because most day-to-day topics are not formal cases. Example: “My neighbor and I disagree on this matter.” Example: “I haven’t made up my mind on this matter yet.” Using “in this matter” here would sound unnecessarily formal or even confusing.
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Common Mistakes and Misconceptions
The biggest mistake is treating the two phrases as fully interchangeable, when their formality and context differ sharply. Another common error is inserting a hyphen, which is never required. Some writers also assume British English swaps the preposition, but both American and British English follow the same on/in distinction, the difference is topic versus case, not regional spelling.
A third mistake is using “in this matter” to sound more professional in casual emails, which usually has the opposite effect and reads as stiff or confusing.
Quick Reference Guide
- Talking about a topic or opinion: use on this matter
- Referring to a legal case or official proceeding: use in this matter
- No hyphen needed in either phrase
- American and British English follow the same rule
- HR investigations typically use in this matter
- General workplace discussions typically use on this matter
Case Study: Corporate Email Example
Consider two emails from the same HR department. The first reads: “Thank you for sharing your feedback on this matter; we’ll take it into account during the next policy review.” The second reads:
“As part of our internal investigation, we are unable to comment further in this matter.” The first email discusses a general topic openly. The second refers to an active, formal case with defined boundaries. Both are correct because each phrase matches its context.
Why Getting It Right Matters
Small wording choices shape how credible your writing sounds. A lawyer who writes “on this matter” instead of “in this matter” in a court filing risks sounding imprecise about the nature of the case.
A manager who writes “in this matter” in a routine team email risks sounding cold or overly bureaucratic. Mastering the on this matter vs in this matter distinction helps your writing match its intended tone, whether that’s approachable or formally precise.
Visual Aid: Phrase Selection at a Glance
Picture a simple decision point. If you’re commenting from outside a topic, reach for “on this matter.” If you’re referring to something you’re formally inside of, like a case, file, or dispute, reach for “in this matter.” That single mental image resolves most real-world uses.
On This Matter vs In This Matter: Quick Quiz
Test what you’ve learned with this short knowledge check.
1. Which sentence is correct for a general team discussion? A) “I’d like your thoughts in this matter.” B) “I’d like your thoughts on this matter.”
2. Which sentence fits a court filing? A) “The judge has ruled in this matter.” B) “The judge has ruled on this matter.”
3. True or False: A hyphen is required in “in-this-matter.” A) True B) False
4. Which phrase fits an HR investigation update? A) “We cannot comment further in this matter.” B) “We cannot comment further on this matter.”
Answer Key:
- B — General team feedback is a topic discussion, so “on this matter” fits.
- A — A court ruling refers to an active case, so “in this matter” fits.
- B, False — Neither phrase takes a hyphen under any major style guide.
- A — Formal investigations are treated as cases, so “in this matter” fits.
Conclusion
The on this matter vs in this matter choice isn’t about personal preference, it’s about matching the phrase to the situation. “On this matter” belongs in everyday conversations, business emails, and general discussions where you’re commenting on a topic. “In this matter” belongs in legal filings, HR investigations, and formal proceedings where a specific case is already underway.
Once you internalize that simple topic versus case distinction, you’ll never second-guess this phrase again. Whether you’re drafting a client email or reviewing a legal document, choosing correctly between on this matter vs in this matter signals precision and confidence in your writing, two qualities that readers and colleagues notice immediately.
Arthur Whitmore is a passionate grammar enthusiast and language writer at Hexobrust.com. He creates clear, helpful content on grammar, spelling, and everyday English to make learning simple and enjoyable.
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