Period After Quotation
The convention governing whether a period goes inside or outside closing quotation marks.
Period-after-quotation is the shorthand name for the American and British disagreement about where the full stop belongs when a quotation ends a sentence. American style (and the style of most international publishers) places the period inside the quotation marks: She said, 'Hello.' British style places it outside unless the period is part of the original quotation: She said, 'Hello'.
The difference is not arbitrary. American style treats quotation marks as a kind of punctuation enclosure; British style treats them as a boundary that should not absorb punctuation that belongs to the surrounding sentence. Neither is wrong; mixing them in the same document is.
The question is more complicated when the quoted material already ends with a period or when a citation follows the quotation. Most style guides have specific rules for those cases; the general principle is to avoid giving the reader two periods or none.
Common mistake: applying British logic inside a document that follows American style because the quotation 'looks better' that way. Consistency with the chosen style guide is the rule.
“American: She said, 'I'm leaving.' British: She said, 'I'm leaving'.”
Keep reading the glossary
The rule — differing on either side of the Atlantic — for where the comma and period sit relative to a closing quotation mark.
The punctuation that signals direct speech or a quoted phrase — single or double, depending on locale.
Placing punctuation inside quotation marks only when it belonged to the quoted material.
A national style difference — double in American English, single in much of British English.