Most styles keep “of” lowercase in titles, unless it’s the first or last word, or the first word after a colon.
If you’ve ever stared at a headline and thought, “Wait… should that tiny word be capped?”, you’re not alone. “Of” is short, it shows up a lot, and it sits right in the spot where your eye catches it. The good news: you can decide in seconds once you know which casing system you’re using.
| Where “of” appears | Capitalize “of”? | Quick sample |
|---|---|---|
| Middle of a title in title case | No | The Sound of Music |
| First word of a title | Yes | Of Mice and Men |
| Last word of a title | Yes | Rules to Write Of |
| First word after a colon (title case) | Yes | Editing Titles: Of Style and Choice |
| Inside a proper name | Usually no | University of Dhaka |
| Inside a quoted or branded title | Match the original | “House Of Cards” (brand styling) |
| Sentence case titles | No (unless first word) | Study of classroom seating |
| All-caps headings | Style choice, not grammar | THE SOUND OF MUSIC |
Should “Of” Be Capitalized In A Title? Rules By Style
Start by naming the casing system. Lots of confusion comes from mixing rules from two systems that work in different ways. In most blog headlines and book titles, people use title case. In many UI labels and some academic contexts, you’ll see sentence case.
Title case in plain terms
Title case means you capitalize the “big” words: nouns, verbs, adjectives, adverbs, and pronouns. Short function words such as articles, short conjunctions, and prepositions usually stay lowercase. “Of” lands in that last group, so it stays lowercase most of the time.
Sentence case in plain terms
Sentence case is closer to normal sentence capitalization. You cap the first word, proper nouns, and a few special cases like acronyms. In sentence case, “of” stays lowercase unless it starts the title.
Got a style sheet? Use it. No style sheet? Pick one guide and apply it to every headline, subhead, and menu label. Readers won’t notice one choice; they will notice mixed caps.
Why “of” is treated as a lowercase word
Most style guides treat prepositions as “minor” words in title case, so they don’t take capitals in the middle of a title. That rule keeps headings readable and consistent, especially when a title has many short connector words. The Chicago Manual of Style Q&A spells out that prepositions stay lowercase in titles except at the start or end.
When “of” Gets A Capital Letter
“Of” earns a capital letter in a title far less often than people think. Still, there are a few spots where it’s correct, and those spots show up in real writing all the time.
When “of” is the first word
If the title begins with “of,” capitalize it. This is true in title case and sentence case. It also applies when a subtitle starts with “of” after a colon, since that “of” becomes the first word of that subtitle in most title-case systems.
When “of” is the last word
If a title ends with “of,” capitalize it. Ending a title with “of” can feel odd in natural English, but it can happen in stylized headings, quiz prompts, or paired titles where the second half is implied.
When a colon creates a new “first word”
Many title-case systems capitalize the first word after a colon in a title. So if you write a title like Editing Titles: Of Style and Choice, that “Of” gets capped because it’s the first word after the colon. This rule is also common after an em dash used as a subtitle break.
When you’re preserving official styling
Brand names and published titles can follow their own casing. If you’re referring to a show, product, album, or campaign that prints “Of” with a capital letter, you may choose to keep it that way, since you’re reproducing a proper title. For school work, check your instructor’s style rules before you copy a brand’s stylized casing.
Style Guide Differences That Change The Answer
People ask about “of” because they’ve seen it capped in some places and not in others. Often that’s a style choice, not a grammar change. Three patterns show up most often.
Chicago and MLA: lowercase prepositions in titles
Chicago’s headline-style rule keeps prepositions lowercase in the middle of a title. That means “of” stays lowercase unless it sits at the start or end, or it starts a subtitle after a colon. Many editors follow a similar pattern for MLA-style title capitalization too.
AP and APA: word-length shortcuts
Some systems capitalize longer prepositions while leaving short ones lowercase. Under that kind of rule, “of” still stays lowercase because it has two letters. The larger change shows up with words like “between” or “through,” which some guides cap and others don’t.
Microsoft style: sentence case is the default
In Microsoft’s guidance for modern UI and docs, sentence case is often preferred for headings, since it reads like normal text. When your project uses title-style capitalization, Microsoft still treats short words like articles and many prepositions as lowercase in the middle of a title. See the Microsoft Style Guide capitalization rules for the official wording and examples.
Title Case Checks That Catch “of” Errors
Here’s a quick way to stop second-guessing. Run these checks in order. You’ll end up with a consistent title, and you’ll stop “fixing” titles that were already right.
Check 1: Are you using title case or sentence case?
If your site uses title case for posts and headings, treat “of” as a lowercase word unless it’s first or last, or it starts the subtitle after a colon. If your site uses sentence case, “of” stays lowercase unless it starts the title.
Check 2: Is “of” the first or last word on a line?
Line breaks can fool the eye. A title might wrap on mobile so “of” starts a new line, while it isn’t the first word of the title. Capitalize based on the title’s real word order, not where the line wraps.
Check 3: Is “of” right after a colon?
If the word after the colon is “of,” many title-case systems cap it as the first word of the subtitle. If your house style keeps the word after a colon lowercase unless it’s a “big” word, follow that rule across all titles so your site feels consistent.
Check 4: Are you matching a published title?
If you’re naming a book, film, or series, you can keep the official casing as printed on the front or the publisher’s page. This can override your house title-case rule in running text, since it’s a proper title.
Examples You Can Copy Without Hesitation
Below are titles that look similar at a glance but follow different logic. Each one uses “of” in a different spot. If you pattern-match the slot, you’ll fix most titles in a snap.
Middle-of-title “of” in title case
- Rules of Academic Writing
- The Art of Clear Headings
- Power of Small Changes
First-word “Of” in title case
- Of Mice and Men
- Of Time and Memory
After-a-colon “Of” in title case
- Grammar Choices: Of Style and Tone
- Study Skills: Of Notes and Revision
Common Traps With “of”
Most “of” mistakes come from one of three traps: overusing a title-case converter, copying casing from a logo, or mixing rules from two style guides in the same site. Here’s how to dodge each one.
Trap 1: Auto title-case tools that don’t match your style
Online converters can be handy, but they don’t all follow the same guide. One tool might cap every word longer than three letters. Another might lowercase all prepositions. If you rely on tools, pick one style rule set and stick with it.
Trap 2: Brand styling that breaks normal casing
Brands sometimes cap “Of” for design balance. That’s fine for a logo. It can look odd in running text, blog headings, or reference lists. If you keep the brand’s styling, keep it for that specific title only, not for all your headings.
Trap 3: “Title case” mixed with “every word capped”
Some people treat title case as “Cap Every Word.” That’s a different style, and it creates uneven results once you start adding short words like “a,” “an,” “the,” and “of.” If your aim is standard title case, keep “of” lowercase in the middle.
Practice Fixes With Real Draft Titles
This table shows draft titles that show up in student work and blog posts. Each fix follows the usual title-case rule: keep “of” lowercase unless it starts or ends the title, or it begins the subtitle after a colon.
| Draft | Clean title case | Reason |
|---|---|---|
| Rules Of Essay Writing | Rules of Essay Writing | “of” sits in the middle |
| The Power Of Habit | The Power of Habit | preposition in the middle |
| Of grammar and tone | Of Grammar and Tone | first word gets capped |
| Editing titles: of style and choice | Editing Titles: Of Style and Choice | first word after a colon |
| University Of Dhaka policies | University of Dhaka Policies | “of” stays lowercase in names |
| Secrets of Of in headlines | Secrets of of in Headlines | second “of” is not a title break |
| How to write of | How to Write Of | last word gets capped |
| THE SOUND OF MUSIC | The Sound of Music | all-caps is a design choice |
| Errors: of punctuation and spacing | Errors: Of Punctuation and Spacing | subtitle begins with “of” |
Mini Checklist Before You Publish
If you want a one-pass check, run this list. It’s short on purpose. You’ll catch the “of” issue and a few nearby casing slips at the same time.
- Pick a casing system for your site or document: title case or sentence case.
- In title case, cap the first and last word, plus nouns, verbs, adjectives, adverbs, and pronouns.
- In title case, keep “of” lowercase in the middle of the title.
- Cap “Of” if it is the first word, the last word, or the first word after a colon.
- If you’re reproducing a published title with its own styling, match that styling for that one title.
- Scan the title on mobile to make sure a line break didn’t trick your eye.
Still unsure? Drop your title into a draft, apply one style rule set, and stick with that rule set across the site. Consistency does more for reader trust than one-off “fixes” that change title casing from page to page.
And if your question is Should “Of” Be Capitalized In A Title?, the safe default for most English title case is: keep “of” lowercase unless it starts or ends the title, or it starts the subtitle after a colon.
You can reuse that same rule when the same question pops up again: Should “Of” Be Capitalized In A Title? Stick with one guide, and the answer stops wobbling.