APA vs MLA: Which Citation Style Should You Use?

If you have ever stared at a syllabus wondering whether your paper needs parenthetical author-date citations or author-page references, you are not alone. APA and MLA are the two most widely assigned citation styles in North American colleges and universities, yet they follow fundamentally different philosophies about how to credit sources. This guide walks through the history, rules, and practical differences so you can choose the right style, format it correctly, and avoid the most common mistakes.

A Brief History of Each Style

APA (American Psychological Association) published its first style guidelines in 1929 as a seven-page article in the Psychological Bulletin. The goal was to standardize scientific manuscript preparation across psychology journals. Over nearly a century the guidelines grew into the Publication Manual of the American Psychological Association, now in its 7th edition (2020). APA style emphasizes when research was published because currency of evidence matters in the sciences. That is why the publication year appears immediately after the author name in every citation.

MLA (Modern Language Association) was founded in 1883 by a group of language and literature scholars at Johns Hopkins University. Its citation guidelines evolved through the MLA Handbook, which reached its 9th edition in 2021. MLA style is built around the idea of containers - a source can live inside a larger work (an article in a journal, a chapter in a book, a page on a website). Because humanities scholars often analyze primary texts passage by passage, MLA prioritizes page numbers over dates in its in-text citations.

Understanding these origins explains almost every formatting difference you will encounter. APA asks "who said it and when?" while MLA asks "who said it and where on the page?"

Key Differences at a Glance

The table below summarizes the most important divergences between APA 7th edition and MLA 9th edition. Refer to Chapter 8 of the APA Publication Manual and Chapter 5 of the MLA Handbook for the authoritative rules on in-text citations.

Use this table as a quick-reference checklist when you are formatting your paper. For an even faster workflow, try the APA 7 citation generator or the MLA 9 citation generator to produce correctly formatted entries automatically.

Which Disciplines Use Which Style?

Choosing between APA and MLA is rarely a personal preference - it is determined by your field of study. The table below maps common disciplines to their expected style.

Sciences and social sciences (APA)

• Psychology and counseling
• Sociology and social work
• Education and educational technology
• Nursing, public health, and health sciences
• Business, economics, and marketing
• Political science and criminal justice
• Linguistics (empirical research)
• Engineering (some departments; others use IEEE)

Humanities and liberal arts (MLA)

• English composition and literature
• Comparative literature and foreign languages
• Cultural studies and media studies
• Philosophy and religious studies
• Art history and music history
• Theater and film studies
• Creative writing workshops

If your professor has not specified a style, check the department's website or look at published journals in your field. A psychology journal will almost certainly require APA; a literary journal will expect MLA. Our citation styles overview page lists additional formats such as Chicago, IEEE, and Vancouver if neither APA nor MLA fits your discipline.

In-Text Citations: A Deeper Look

The in-text citation is the piece most visible to your reader, so getting it right is critical. For a broader overview of in-text citation mechanics across styles, see our complete guide to in-text citations.

APA in-text rules (Chapter 8 of the Publication Manual)

• Parenthetical: (Smith, 2024)
• Narrative: Smith (2024) argued that...
• Two authors: (Smith & Jones, 2024)
• Three or more authors: (Smith et al., 2024) from the very first mention
• Direct quote: (Smith, 2024, p. 12) - page number required for direct quotations
• No author: Use a shortened title in italics or quotation marks depending on source type

MLA in-text rules (Chapter 5 of the MLA Handbook)

• Parenthetical: (Smith 45)
• Narrative: Smith argues that... (45)
• Two authors: (Smith and Jones 45)
• Three or more authors: (Smith et al. 45)
• No page number: (Smith) - omit page number when the source is unpaginated, such as most websites
• No author: Use a shortened title in italics or quotation marks

Tip: The fastest way to tell which style a paper uses is to look at the in-text citations. A year in parentheses means APA. A bare page number without a year means MLA.

Formatting Deep-Dive

Both styles share some universal formatting conventions - double spacing, 0.5-inch hanging indents on reference entries, and 1-inch margins - but they diverge on several visual details.

Page headers

In APA, every page carries a running head (a shortened version of the paper title in uppercase, flush left) and a page number flush right. Section 2.18 of the Publication Manual specifies that the running head should be no more than 50 characters. Student papers may omit the running head if the instructor permits.

In MLA, there is no running head. Instead, the author's last name and the page number appear in the upper-right corner of every page, half an inch from the top.

Title page versus first-page header

APA requires a separate title page (Section 2.3). For student papers this includes the paper title, the author name, the institutional affiliation, the course number and name, the instructor name, and the assignment due date - all centered and double-spaced.

MLA does not use a title page. Instead, the author's name, the instructor's name, the course title, and the date appear in the upper-left corner of the first page, each on its own line. The paper title follows, centered, in plain text (no bold, no underlining).

Heading levels

APA defines five heading levels (Section 2.27). Level 1 is centered and bold. Level 2 is left-aligned and bold. Level 3 is left-aligned, bold, and italic. These structured headings help organize empirical research into recognizable sections like Method, Results, and Discussion.

MLA does not prescribe heading levels. Many MLA papers have no headings at all, especially short essays. When headings are used, the MLA Handbook recommends consistency but does not mandate a specific hierarchy.

Font and spacing

APA 7th edition expanded the list of acceptable fonts (Section 2.19) to include 12-point Times New Roman, 11-point Calibri, 11-point Arial, and 11-point Georgia, among others. The guiding principle is accessibility and readability.

MLA recommends 12-point Times New Roman but accepts any easily readable font of the same size.

Both styles require double spacing throughout the entire document, including the reference list or Works Cited page, block quotations, and footnotes.

Constructing Reference Entries

The shape of a reference entry differs significantly between the two styles. Below are examples for common source types so you can see the patterns side by side.

Book with one author

• APA: Smith, J. A. (2024). Writing with clarity: A guide for students. Academic Press.
• MLA: Smith, John Adams. Writing with Clarity: A Guide for Students. Academic Press, 2024.

Journal article with DOI

• APA: Lee, R., & Patel, S. (2023). The impact of remote learning on student engagement. Journal of Higher Education, 44(2), 112--130. https://doi.org/10.1000/example
• MLA: Lee, Rachel, and Sanjay Patel. "The Impact of Remote Learning on Student Engagement." Journal of Higher Education, vol. 44, no. 2, 2023, pp. 112--30. doi:10.1000/example.

Website

• APA: World Health Organization. (2025, January 15). Mental health in the workplace. https://www.who.int/example
• MLA: World Health Organization. "Mental Health in the Workplace." World Health Organization, 15 Jan. 2025, www.who.int/example.

For step-by-step instructions on citing web sources in APA, see our guide on how to cite a website in APA 7.

Notice the key patterns: APA places the date immediately after the author, uses initials instead of full first names, and renders titles in sentence case. MLA spells out first names, uses title case, places the date later in the entry, and concludes most entries with a period.

When You Might Need Both Styles

Most students will use one style at a time, but there are situations where familiarity with both is essential.

Double majors and interdisciplinary programs. A student majoring in psychology and English literature will write APA papers for research methods courses and MLA papers for literary analysis seminars, sometimes in the same semester. Keeping a quick-reference card (or bookmarking this article) prevents cross-contamination of styles.

Graduate-level interdisciplinary research. A thesis on the psychology of narrative, for example, might draw on both empirical studies (APA territory) and literary criticism (MLA territory). In these cases, your thesis advisor or department will specify a single style. You must then reformat all sources into that one system, even if the original works are more commonly cited in the other style.

Publishing across fields. An academic who publishes in both a social science journal and a humanities journal will need to reformat the same bibliography repeatedly. Understanding the logic behind each system - rather than memorizing rules - makes this far less painful.

Important: You should never mix APA and MLA within a single paper. Choose one and apply it consistently from the first page to the last. Inconsistent citation formatting is one of the most common reasons instructors deduct points.

Tools and Official Resources

When in doubt, consult the primary sources:

• Publication Manual of the American Psychological Association, 7th edition (2020). ISBN 978-1-4338-3217-8. The definitive reference for APA style, covering everything from bias-free language (Chapter 5) to reference examples (Chapters 10--11).
• MLA Handbook, 9th edition (2021). ISBN 978-1-60329-262-7. The official guide for MLA style, including the core elements system for building citations (Chapter 5) and detailed formatting advice (Chapter 1).

Free online supplements are also available:

• Purdue OWL: APA Style - clear summaries of APA formatting rules with sample papers.
• Purdue OWL: MLA Style - the same quality of guidance for MLA, including Works Cited examples.

You can also generate correctly formatted references instantly with our free tools. The APA 7 citation generator and the MLA 9 citation generator accept a URL, DOI, or ISBN and produce a ready-to-paste entry. Browse all supported formats on the citation styles page.