That single, lonely “M” on a wedding RSVP card has confused more guests than almost any dress code ever could. Pens hover, brows furrow, and suddenly a simple RSVP feels like a test. Are you supposed to write “Maybe”? Your middle name? Your meal choice? The truth is much simpler—and once you know it, you’ll never look at that little “M” the same way again.

The mysterious “M” is simply the first letter of a traditional courtesy title: Mr., Mrs., Ms., or Miss. You’re expected to complete the title and then write your full name on the line. So “M” becomes “Mr.,” “Mrs.,” “Ms.,” or “Miss,” followed by your name. It isn’t asking about your meal, marital status, or number of guests—it’s simply asking who you are.

If your preferred title doesn’t begin with M, you can write the title you actually use or skip the title and provide your name. And if you’re designing invitations, you don’t have to use the “M” format at all. A simple “Name:” line is clearer and avoids unnecessary confusion. In the end, the real RSVP rule is easy: respond on time, use the name you want to be called, and only respond for the people who were actually invited.