Do speech marks end after a full stop?

That depends on whether the full stop is part of the quoted material or not! Here's a breakdown:

1. Full stop inside the quotation:

* If the full stop is part of the original quoted text, it goes inside the closing speech marks.

Example: She said, "I'm going to the store."

2. Full stop outside the quotation:

* If the full stop is not part of the original quoted text, it goes outside the closing speech marks.

Example: He asked, "Where are you going?" and then walked away.

Remember: The punctuation should reflect the meaning and grammar of the sentence.