Short Answer
"Of" is generally lowercase in middle positions and capitalized only when it is first or last in a title.
Rule (Part-of-Speech Logic)
Part of speech: Preposition
"Of" is a short preposition and is normally lowercase in middle position for title case, with capitalization at title edges.
"Of" is a short preposition and should stay lowercase in most middle positions. Capitalize only when placement requires it.
Style notes quick scan
- "Of" is usually lowercase in the middle.
- AP lowercases short middle prepositions like "of".
- APA follows the same short-preposition treatment in middle positions.
- MLA generally keeps short middle prepositions lowercase.
- Chicago keeps short middle prepositions lowercase unless position overrides.
According to Style Guides (Middle Position)
- According to Standard style: not capitalized.
- According to AP style: not capitalized.
- According to APA style: not capitalized.
- According to MLA style: not capitalized.
- According to Chicago style: not capitalized.
✓ Do
History of Modern Marketing
✗ Do not
history of modern marketing
Special Cases
- Capitalize "of" when first or last.
- Preserve official capitalization in formal names and quoted works.
- When consolidating SEO pages, keep one canonical rule phrasing to avoid duplicate intents.
Why People Get This Wrong
It appears in many proper titles, so writers sometimes memorize exceptions and accidentally apply them as a universal rule.
Attested Usage (Practice Evidence)
These are observed editorial usage patterns, not absolute grammatical authority.
Origin / Meaning (Optional)
"Of" developed from Old English "of" and marks relation, source, or composition.
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About Oleh Kovalenko
Oleh Kovalenko develops practical capitalization guidance for editorial and SEO workflows, with a focus on consistent rule application.
