Result
Yes. "Do" is a verb, either the main verb ("Just Do It") or a helping verb ("Why Do Headlines Matter?"). Every style guide capitalizes verbs in a title, so "Do" gets a capital even though it is only two letters long.
"Do" by Style Guide
| Style guide | "Do" mid-title | Why |
|---|---|---|
| AP | Capitalize | Verbs are major words |
| APA | Capitalize | Verbs are major words |
| Chicago | Capitalize | Verbs are major words |
| MLA | Capitalize | Verbs are major words |
| AMA | Capitalize | Verbs are major words |
| Bluebook | Capitalize | Verbs are major words |
Examples in Chicago Style
- What Do Readers Want
- How Do You Write a Good Title
- Things to Do in Chicago
- Do More with Less
Helping Verb or Not, It Is Capitalized
Some writers lowercase "do" in questions because it seems like filler: "What do Readers Want?" Style guides make no exception for helping verbs. "Does", "did", "don't," and "doesn't" are all capitalized too.
Related Words
Other short verbs include "be", "go", "is", and "has". For the words that do stay lowercase, see the full list of words that stay lowercase.
"Do" in Sentence Case
APA reference lists, many news sites, and most UI text use sentence case instead of title case. There, only the first word and proper nouns get capitals, so "do" is lowercase unless it starts the title: "What do readers want." Pick one of the two styles for a whole set of headings rather than mixing them.
Quick Answers
Should "do" be capitalized in a title?
Yes. "Do" is a verb, and every style guide capitalizes verbs.
Is "do" capitalized in a question title?
Yes. As a helping verb in a question ("Why Do Headlines Matter?"), it is still capitalized.
Is "don't" capitalized in a title?
Yes, as "Don't." Contractions of verbs are capitalized.