The rules for citing multiple authors depend on which style guide you’re using and how many authors the source has. APA, MLA, and Chicago all handle multi-author citations differently, but they share one thing in common: once you hit three or more authors, you’ll almost always shorten the citation with “et al.” (Latin for “and others”) in the body of your paper. The reference list or bibliography at the end is where the styles diverge most. Here’s exactly how each one works.
APA Style (7th Edition)
In-Text Citations
APA draws a clean line at two authors. If your source has one or two authors, you name them every single time you cite the work. For three or more authors, you use only the first author’s last name followed by “et al.” from the very first citation onward.
There’s one formatting detail that trips people up: APA uses an ampersand (&) when the names appear inside parentheses, but spells out “and” when the names appear in your sentence. So a parenthetical citation looks like (Salas & D’Agostino, 2020), while a narrative citation reads Salas and D’Agostino (2020). For three or more authors, both versions look the same: (Martin et al., 2020) or Martin et al. (2020).
Reference List
The reference list at the end of your paper is more inclusive. For sources with up to 20 authors, list every single one. Separate names with commas, put an ampersand before the final name, and format each as last name followed by initials. A three-author entry would look like this:
Martin, R. A., Lee, S. K., & Patel, N. (2020). Title of article. Journal Name, 12(3), 45–67.
For sources with 21 or more authors, list the first 19 names, insert an ellipsis (. . .), and then add the final author’s name.
MLA Style (9th Edition)
In-Text Citations
MLA’s rule is straightforward: for a source with one or two authors, list their names. For three or more, use only the first author’s last name plus “et al.” This applies whether the citation is parenthetical or woven into your sentence.
A parenthetical citation with three or more authors would look like (Franck et al. 327), with the page number following without a comma. In a narrative citation, you’d write: According to Franck et al., “Current agricultural policies in the U.S. are contributing to the poor health of Americans” (327).
Note that MLA does not use a year in the in-text citation, only the author name(s) and page number. This is one of the easiest ways to distinguish MLA from APA at a glance.
Works Cited
On the Works Cited page, MLA follows the same three-author threshold. For a source with one or two authors, list all names. For three or more, list only the first author’s last name and first name, followed by “et al.” This makes MLA’s Works Cited entries shorter than APA’s reference entries for the same source. An example:
Franck, Caroline, et al. “Agricultural Subsidies and the American Obesity Epidemic.” American Journal of Preventative Medicine, vol. 45, no. 3, Sept. 2013, pp. 327–333.
Chicago Style (17th Edition)
In-Text Citations (Author-Date)
Chicago’s author-date system, commonly used in the sciences and social sciences, works similarly to APA for in-text citations. For two authors, name both every time. For three or more, use only the first author’s last name followed by “et al.”
Bibliography or Reference List
The reference list is where Chicago stands apart. For two authors, list both names. For three to six authors, list all of them. Once a source exceeds six authors, list the first three followed by “et al.” This middle ground between APA (which lists up to 20) and MLA (which lists only the first) makes Chicago unique.
If you’re using Chicago’s notes-bibliography system (footnotes or endnotes instead of parenthetical citations), the same author thresholds apply. Your first footnote for a source typically includes the full citation, while subsequent footnotes use a shortened form.
Quick Reference by Author Count
- Two authors: All three styles list both names in every in-text citation and in the bibliography or reference list. APA uses an ampersand inside parentheses and “and” in narrative text. MLA and Chicago use “and” in both places.
- Three or more authors (in-text): All three styles use only the first author plus “et al.”
- Three or more authors (reference list): APA lists all authors up to 20. MLA lists only the first author plus “et al.” Chicago lists all authors up to six, then switches to the first three plus “et al.” for seven or more.
Formatting “Et Al.” Correctly
“Et al.” is short for “et alia.” The word “et” is a complete Latin word meaning “and,” so it never gets a period. The “al.” is an abbreviation, so it always gets a period. Write it as et al. with a period after “al” only.
In APA, a comma precedes the year after “et al.” in parenthetical citations: (Martin et al., 2020). In MLA, no comma separates “et al.” from the page number: (Franck et al. 327). These small punctuation differences matter when your professor or editor is checking your formatting.
One more detail: “et al.” is not italicized in any of the three major styles, even though it’s a Latin phrase. This is because it’s considered standard English usage in academic writing.
When Two Citations Look the Same
Sometimes shortening to “et al.” creates a problem. If you’re citing two different sources that both have the same first author and the same year, (Smith et al., 2022) could refer to either one. In APA, the fix is to include enough additional author names to distinguish the two citations. If one source is by Smith, Lee, and Patel and the other is by Smith, Rivera, and Chen, you’d write (Smith, Lee, et al., 2022) and (Smith, Rivera, et al., 2022). MLA and Chicago handle this similarly, adding just enough names to make each citation unique.
This situation comes up more often than you’d expect in literature reviews or research-heavy papers where you’re citing several works by prolific authors in the same field.