It Depends
The Title Rule
"Professor" follows the same capitalization logic as "president," "senator," and "doctor." It's a title – and titles are capitalized when they work as part of someone's name, not when they describe a general role.
Write Professor Chen the same way you'd write Dr. Chen. The title functions like a first name in that position – it identifies a specific person. Remove the name and the capital letter usually goes with it: The professor assigned extra reading.
This is the single most common mistake with "professor." People capitalize it out of respect, but capitalization in English isn't about importance – it's about whether a word is functioning as a proper noun or a common noun.
Quick Rules
Capitalize when
- It's a title before a name: Professor Williams will hold office hours.
- It's used as a direct form of address: Thank you, Professor, for your feedback.
- It's part of a named/endowed position: the John Smith Professor of Law (official title)
- It starts a sentence (like any word)
Keep lowercase when
- It describes the role: She became a professor at 35.
- It follows a name: Emily Hart, professor of biology, published new findings.
- It refers to professors in general: The professors met to discuss the curriculum.
- It's used as an adjective: a professor's office, the professor emeritus
Tip: If you can swap "professor" with "teacher" and the sentence still reads the same way, it's being used as a description – keep it lowercase.
AP Style vs. Chicago Style
AP and Chicago agree on this one more than they disagree.
Both styles capitalize "Professor" before a name: Professor Angela Davis. Both lowercase it after a name or when used as a standalone description: the professor spoke at the event.
The small difference: AP style abbreviates most titles before names but does not abbreviate "Professor" – it's always written in full. You'd write Prof. only in informal contexts or tables, never in AP news copy.
Chicago is a bit more flexible. CMOS allows "Prof." as an abbreviation in running text when used before a full name, though spelling it out is always preferred.
For academic writing specifically, APA follows the same general rule – lowercase for descriptions, capitalize before names – and adds that you should generally avoid using courtesy titles like "Professor" in favor of full names on first reference.
Examples
✓ Do
- Professor Garcia teaches microeconomics on Tuesdays.
- The university hired three new professors this year.
- I emailed my professor about the deadline extension.
- Sarah Lin, professor of art history, curated the exhibition.
✗ Do not
The Professor canceled class today.
No name follows – it's a generic reference. Lowercase: The professor canceled class today.
She's a Professor of Mathematics.
Job description, not a title before a name. Lowercase: She's a professor of mathematics.
I asked professor Adams for a recommendation.
Title before a name must be capitalized: I asked Professor Adams for a recommendation.
Edge Cases Worth Knowing
These are the scenarios where "professor" causes the most hesitation – especially in academic writing and emails.
- "Prof." abbreviation. Capitalize and punctuate: Prof. Tanaka. In formal writing, spell it out: Professor Tanaka. Never use the abbreviation without a name following it.
- Professor emeritus. Lowercase "emeritus" in running text: professor emeritus, professor emerita. When used as a title before a name, capitalize the title portion: Professor Emeritus John Walker. Some institutions capitalize both words as an official designation – follow your institution's style if writing for an academic audience.
- Adjunct, associate, assistant. These modifiers stay lowercase when describing a rank: She's an associate professor. Before a name, capitalize: Associate Professor Diane Rivera. The full rank functions as the title.
- Visiting professor. Same pattern: a visiting professor from Berlin (lowercase) vs. Visiting Professor Hans Weber (before a name).
- Emails to professors. When addressing a professor directly – "Dear Professor Kim" – capitalize. In the body of the email, follow normal rules: As the professor mentioned in lecture... (lowercase, no name attached).
Frequently Asked Questions
Writing a heading with "Professor" in it? Our free Title Case Converter handles AP, APA, Chicago, and MLA styles automatically.
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About Sophia Stewart
Sophia Stewart develops practical capitalization guidance for editorial and SEO workflows, with a focus on consistent rule application.
