Et Al With Period | The Citation Mark That Matters

If you’ve paused over Et Al With Period while editing a paper, you’re not alone. This tiny mark trips up students, bloggers, researchers, and editors because it looks simple until a style manual, a teacher, or a journal asks for clean citation form. The good news is that the base rule is steady: write et al. with a period after al., not after et.

That dot is there for a plain reason. Et is a full Latin word meaning “and.” Al. is shortened from a longer Latin word meaning “others.” Since only one part is shortened, only one part gets the period. Once that clicks, the punctuation stops feeling random.

This article clears up where the period goes, when a comma belongs near it, how major citation styles handle it, and the spots where writers usually slip. By the end, you should be able to scan your own citations and fix them in seconds.

Why Only One Word Gets A Period

Writers often treat et al. like one bundled label, then guess at the punctuation. That’s where the mess starts. It is two words with two jobs. One stays whole. One is clipped. So the clipped one takes the mark.

Write it like this: et al.

• et = full word, no period
• al. = shortened word, period stays
• the phrase usually means “and others”

You don’t need a second period right after it unless the sentence itself ends there. In that spot, the same dot does both jobs. You also don’t italicize it in normal citations in most modern style settings. Many writers still do out of habit, mostly because the phrase came from Latin, but current citation practice usually keeps it in regular type.

Et Al With Period In APA, MLA, And Chicago

The spelling stays the same across the big citation systems, though each style has its own rules for when you can shorten a list of names. In APA’s author-date citation system, works with three or more authors are shortened to the first author’s surname plus et al. in the text. Chicago’s author-date style also uses the first name plus et al. in text citations for works with three or more authors. For MLA, the current MLA Handbook is the official place to verify how many names to show before you shorten a citation.

What changes from style to style is not the period after al.. What changes is the trigger point. APA shortens sooner than older systems did. MLA uses et al. in parenthetical citations and works-cited entries once a source has more than two authors. Chicago gives you one rule for the text and another for the reference list, depending on the system you’re using.

That means you should split the job in two. First, lock down the spelling: et al. Then check your style’s rule for how many names stay visible before you shorten. That order keeps you from fixing the wrong problem.

Situation	Correct Form	What To Watch
Plain citation phrase	et al.	Period after al. only
APA parenthetical citation	(Smith et al., 2024)	No comma before et al.
APA narrative citation	Smith et al. (2024)	Year sits after the phrase
MLA parenthetical citation	(Smith et al. 42)	No year in standard MLA in-text form
MLA works-cited entry	Smith, Jane, et al.	Comma comes from the inverted name
Chicago author-date in text	(Smith et al. 2024, 77)	Page number follows year
Sentence ending on the phrase	The study was led by Smith et al.	One period does the full stop too
Wrong doubled punctuation	Smith et al..	Drop the extra dot

Where Writers Get Tripped Up

Most errors don’t come from the phrase itself. They come from the punctuation parked around it. A writer learns one style in school, shifts to another at work, then keeps the old comma or old spacing without noticing. That’s why the same four or five mistakes keep showing up.

These are the ones you’ll see most often:

• Adding a period after both words. Wrong: et. al.
• Dropping the period after al. Wrong: et al
• Using a comma in the wrong place. Wrong in APA: Smith, et al.
• Adding two periods at sentence end. Wrong: Smith et al..
• Italicizing the phrase in every citation. Most styles do not ask for that.

Comma Trouble Around Et Al.

The comma issue deserves a closer pass. In APA or Chicago author-date citations, you usually don’t place a comma between the surname and et al. You write “Smith et al.” as one clean unit. In an MLA works-cited entry, you may see a comma before et al. because the first author’s name is reversed, as in “Smith, Jane, et al.” That comma belongs to the name format, not to the phrase by itself.

The One-Period Rule At Sentence End

That same logic helps at the end of a sentence. When a line closes with et al., the period in “al.” also closes the sentence, so you don’t add a second dot. When you spot a comma before et al., ask why it’s there. If the answer is “because this is a reversed name in a bibliography entry,” you’re fine. If the answer is “because it looked right,” it probably isn’t.

When You Should Spell Out Every Name

Et al. is handy, but it isn’t always the right call. Some styles want every author listed in the reference list up to a certain number. Some teachers want all names shown the first time a source appears in class papers. Some journals keep their own house rules on top of APA, MLA, or Chicago.

Use the full list of names when:

1. Your style manual tells you not to shorten that part of the citation.
2. Your instructor, editor, or publisher asks for a house style.
3. Two sources would collapse into the same short form and confuse the reader.
4. You’re writing a sentence in plain prose and not building a formal citation.

That last point catches people off guard. In running text, many editors prefer actual names or a plain English phrase like “Smith and colleagues” over a citation-style abbreviation. It reads better, and it keeps the sentence from sounding like a pasted note. Save et al. for the spots where citation form does the heavy lifting.

Common Slip	Better Form	Why It Reads Cleaner
et. al.	et al.	Only the shortened part takes the period
Smith, et al. (2024)	Smith et al. (2024)	No stray comma in APA narrative form
(Smith et al 2024)	(Smith et al., 2024)	APA keeps the period after al. and a comma before year
(Smith et al., p. 42)	(Smith et al. 42)	Standard MLA drops the comma and “p.” here
Smith et al.. found	Smith et al. found	One period is enough
et al. in every citation	et al. in regular type	Most citation styles keep it plain

A Simple Way To Check Your Citations

If you want a fast editing pass, don’t scan the whole paper at once. Scan only for the phrase. Every time you see it, run the same short test:

1. Is there a period after al.?
2. Is there no period after et?
3. Does the comma pattern match the style you’re using?
4. Is the phrase in regular type unless a style note says otherwise?
5. Would full names work better in plain prose?

That five-step check catches most citation errors in under a minute. It also keeps you from overediting. A lot of writers start tinkering with spacing, commas, and italics when the only fix needed is that one period after al.

If you want one memory trick that sticks, use this line: “et is whole; al. is cut.” That’s the rule in a nutshell. Once you tie the punctuation to the word shape, you stop guessing and start seeing the pattern on sight.

Small marks can make a paper look sloppy or polished. This one tends to punch above its weight. Get et al. right, and your citations feel tighter, your editing moves faster, and your reader never has to pause over a dot that shouldn’t be in doubt.