Academic writing demands precision, and few abbreviations carry as much weight—or cause as much confusion—as "et al." For students, researchers, and professional editors, mastering this tiny Latin phrase is essential for maintaining credibility. While it may seem like a simple shortcut to avoid listing dozens of names, the rules governing its use change significantly depending on whether you are following APA, MLA, Chicago, or Vancouver styles.

The term "et al." is more than just a convenience; it is a fundamental part of scholarly attribution. Using it incorrectly is often perceived as a lack of attention to detail, which can undermine the perceived rigor of a research paper. This analysis provides an exhaustive breakdown of how to use "et al." with perfect accuracy across all major academic disciplines.

Understanding the Meaning and Origin of Et Al

Before applying the rules, one must understand what "et al." actually stands for. It is an abbreviation of the Latin phrase et alii, which literally translates to "and others." In classical Latin, the phrase varied based on the gender and number of the "others" being referenced:

  • Et alii: Masculine plural, used for a group of men or a mixed-gender group.
  • Et aliae: Feminine plural, used exclusively for a group of women.
  • Et alia: Neuter plural, used for inanimate objects or in some scientific contexts.

In modern English academic writing, we use the abbreviated form "et al." to cover all these variations. It is strictly reserved for people. If you are listing things, such as a list of chemicals or book titles, the correct abbreviation is "etc." (et cetera).

Essential Punctuation and Grammar Rules

The most frequent mistakes involve the placement of the period. Because "et" is a full Latin word (meaning "and"), it never takes a period. "Al." is an abbreviation of alii, aliae, or alia, so it must always be followed by a period.

The Period Placement

Correct: Smith et al. Incorrect: Smith et. al. Incorrect: Smith et al Incorrect: Smith et. al

Spacing and Italics

In contemporary academic writing, "et al." is generally not italicized. While older style guides occasionally recommended italics for Latin phrases, the consensus today is that "et al." has been sufficiently "naturalized" into the English language. Unless a specific, niche journal explicitly requests italics, keep it in standard font.

Handling End-of-Sentence Punctuation

A common point of confusion arises when "et al." appears at the end of a sentence. You do not need to add a second period.

  • Correct: The study was conducted by Jones et al.
  • Incorrect: The study was conducted by Jones et al..

However, if the sentence requires a different punctuation mark, such as a comma, semicolon, or question mark, that mark should follow the period.

  • Example: Did the results match the findings of Jones et al.?
  • Example: As noted by Jones et al., the sample size was sufficient.

Usage in APA Style (7th Edition)

The American Psychological Association (APA) significantly simplified its rules regarding "et al." with the release of the 7th Edition in late 2019. For anyone accustomed to the 6th Edition, these changes are critical to note.

In-Text Citations

In the 7th Edition, for any work with three or more authors, you use "et al." starting with the very first in-text citation.

  • Parenthetical: (Miller et al., 2023)
  • Narrative: Miller et al. (2023) argued that...

This is a departure from the 6th Edition, which required listing all authors (up to five) in the first citation and only using "et al." in subsequent mentions. The current rule reduces clutter and recognizes that readers can find the full list in the reference section.

The Exception: Disambiguation

There is a specific scenario where you must list more names to avoid confusion. If you have two different sources from the same year with the same lead author, and the first few authors are also the same, you must list enough names to distinguish the two works.

  • Source A: Smith, Jones, Miller, & Davis (2022)
  • Source B: Smith, Jones, Thompson, & Wu (2022)
  • Citation for A: (Smith, Jones, Miller, et al., 2022)
  • Citation for B: (Smith, Jones, Thompson, et al., 2022)

Reference List

In the APA reference list at the end of the document, "et al." is rarely used. You are expected to list up to 20 authors by name. If a work has 21 or more authors, you list the first 19, insert an ellipsis (...), and then list the final author's name.

Usage in MLA Style (9th Edition)

The Modern Language Association (MLA) style is commonly used in humanities and literature. Its rules for "et al." are straightforward but differ from APA in placement.

In-Text Citations

For sources with three or more authors, MLA requires using the first author’s name followed by "et al." in every instance.

  • Format: (Lastname et al. PageNumber)
  • Example: (Williams et al. 42)

Note that in MLA, there is no comma between the author's name and "et al.", nor is there a comma between "et al." and the page number.

Works Cited List

In the Works Cited section, the same rule applies. If there are three or more authors, you list only the first author (Last Name, First Name) followed by a comma and "et al."

  • Example: Williams, Sarah, et al. The History of Modern Art. Penguin, 2021.

Usage in Chicago Manual of Style

The Chicago Manual of Style (CMOS) is often considered the most complex because it provides rules for both the Notes/Bibliography system (common in history) and the Author-Date system (common in sciences).

Notes and Bibliography System

  • In the Bibliography: You should generally list all authors (up to 10). If there are more than 10 authors, list the first seven followed by "et al."
  • In the Notes (Footnotes/Endnotes): For a work with one to three authors, list all names. For a work with four or more authors, list the first author followed by "et al."

Author-Date System

Similar to APA, the Chicago Author-Date system uses "et al." for works with four or more authors in the in-text citations.

  • Example: (Garcia et al. 2020)

Usage in Vancouver Style

Vancouver style is the standard for most medical and scientific journals. It is a numbered system where citations in the text are indicated by superscript or bracketed numbers.

The Reference List

The use of "et al." in the reference list depends on the specific journal's requirements, but the standard NLM (National Library of Medicine) rule is:

  • List the first six authors, followed by a comma and "et al." if there are more than six authors.
  • Some journals may require listing only the first three authors before using "et al."

The Possessive Form of Et Al

One of the trickiest grammatical hurdles is making "et al." possessive. Since "et al." is a plural abbreviation, the apostrophe and "s" must be placed after the period.

  • Correct: Smith et al.'s (2019) research...
  • Incorrect: Smith's et al. (2019) research...
  • Incorrect: Smiths' et al. (2019) research...

While "Smith et al.'s" is technically correct, many editors find it clunky. A more elegant solution is often to rephrase the sentence: "The research conducted by Smith et al. (2019)..."

Why We Use Et Al: The Ethics of Author Recognition

While "et al." serves the practical purpose of saving space, it is not without controversy in the academic community. The use of this abbreviation effectively "hides" the contributions of junior researchers, graduate students, and lab technicians who may be listed fourth, fifth, or tenth in a long author list.

In the digital age, where page limits for physical journals are less of a constraint, there is a growing movement to discourage the use of "et al." in reference lists. The argument is that every person who contributed to the intellectual merit of a paper deserves to have their name indexed and searchable. However, for in-text citations, "et al." remains a necessary tool to prevent the narrative flow from being interrupted by a half-page list of names.

Common Pitfalls to Avoid

Beyond punctuation, several logical errors frequently plague student papers:

  1. Using Et Al for Two Authors: You should never use "et al." for a source with only two authors. Both names must always be listed.
    • Correct: (Jordan & Pippen, 1996)
    • Incorrect: (Jordan et al., 1996)
  2. Confusing Et Al with Etc.: As mentioned, "et al." is for people; "etc." is for things.
  3. The "Et All" Error: Many writers mistakenly think "al." is an abbreviation for the English word "all." It is not. Writing "et all" is a sign of an unpolished draft.
  4. Incorrect Subject-Verb Agreement: Because "et al." means "and others," it is plural. The verb that follows must reflect this.
    • Correct: Smith et al. argue...
    • Incorrect: Smith et al. argues...

Summary of Rules for Quick Reference

Style In-Text Rule Reference List Rule
APA 7th 3+ authors: (Smith et al., 2023) List up to 20 authors.
MLA 9th 3+ authors: (Smith et al. 12) 3+ authors: Smith, John, et al.
Chicago 4+ authors: (Smith et al. 2023) 10+ authors: List 7, then et al.
Vancouver Numbers only in text. 6+ authors: List 6, then et al.

Frequently Asked Questions

What does "et al." stand for exactly?

It stands for the Latin phrase et alii (masculine/mixed), et aliae (feminine), or et alia (neuter), all meaning "and others."

Should "et al." be in italics?

Generally, no. Most modern style guides (APA, MLA, Chicago) recommend using standard font.

Can I use "et al." if there are only two authors?

No. For two authors, you must list both names in every citation.

Where does the period go in "et al."?

The period only goes after "al." Never put a period after "et" unless it is the end of a sentence.

Is it "et al." or "et. al."?

It is "et al." with no period after "et".

Conclusion

Mastering the use of "et al." is a rite of passage for any serious writer. It requires a balance of linguistic understanding, attention to punctuation, and an awareness of the specific demands of your chosen citation style. While the rules may seem pedantic, they ensure that academic communication remains consistent and professional. By following the guidelines outlined above—particularly the 7th Edition APA updates and the specific punctuation requirements—you can ensure your citations are flawless, allowing your readers to focus on your research rather than your formatting.