MLA Title Case
MLA 9 describes title style as capitalizing the first word, last word, and all principal words. MLA’s public Style Center also documents the traditional lowercase treatment of internal prepositions, but its detailed preposition article is edition-labeled for MLA 8, so this engine does not yet treat the full MLA 9 converter profile as complete.
For MLA 9, capitalize the first word, last word, and principal words. Internal prepositions are normally lowercase in MLA editorial guidance, but the full automated MLA 9 rule profile is not treated as fully deterministic here until all current-edition edge cases are independently covered.
Key details
Important caveats
Automation boundary
This record is public because the human-facing rule is useful and adequately sourced. Automatic MLA conversion is not treated as fully deterministic until compounds, phrasal structures, subtitles, punctuation boundaries, and other current-edition exceptions have deterministic tests.
Further guidance
Current Ninth Edition Core
The MLA Style Center’s ninth-edition handout guidance says to capitalize the first word, the last word, and all principal words when a title is styled in title case.
English And Other Languages
MLA’s Style Center explains that English-language titles use headline/title style, while titles in other languages can follow language-specific sentence-style conventions.
Practical Application
Apply MLA title-style rules by capitalizing the first word, last word, and principal words while normally lowercasing internal articles, coordinating conjunctions, and prepositions according to MLA guidance. Keep the automation fail-closed where current-edition edge cases are not fully reviewed.
Prepositions
MLA’s official Style Center guidance has long treated internal prepositions as lowercase regardless of length. The detailed public article carrying that rule is explicitly labeled for the eighth edition, so the rule is retained as editorial evidence but not used alone to certify a complete ninth-edition automation profile.
Reader Check
Have you identified the word’s role and position under MLA rules rather than copying casing from another style system?
Worked Example
In a title such as “A Guide to Research,” “A,” “Guide,” and “Research” are capitalized, while the internal preposition “to” remains lowercase under the reviewed MLA rule.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- How should I capitalize the title of a handout? (opens in a new tab)MLA Style Center / Modern Language Association · MLA title-style capitalization
- Why does the MLA capitalize certain words in titles? (opens in a new tab)MLA Style Center / Modern Language Association · MLA headline-style rationale and principal/minor-word pattern
- In MLA style, should any part of a two-word preposition be capitalized in a title? (opens in a new tab)MLA Style Center / Modern Language Association · MLA editorial guidance on internal prepositions in titles