The way your wedding invitations are addressed is very important not only for etiquette’s sake, but for logistical reasons, too! When addressing invitations, it sets the tone for the actual wedding and lets the guests know who is invited.
Who is invited: A Family
Address the envelope to the entire family.
The Smith Family
or
To specify which family members are invited, write the names of each family member as a list. The parent or parents’ names will go first, and list invited children in order of age after. Female children under 18 years old should be addressed as Miss.
Mr. and Mrs. John Smith Mr. Evan Smith Miss Eva Smith
Who is invited: A Couple
There are two options for addressing a couple, if they are married or not.
Not Married
Not married but living together
List both names on the same line, starting with whichever person you’re closest with. If you’re equally close with both, list alphabetically:
Ms. Daisy Jones and Mr. William Smith
Not married and do not live together
You could send separate invitations, or one invitation to the person you are closest to.
Married
Same last name
You can list them together just using the husband’s first and last name:
Mr. and Mrs. William Smith
or
You can use both the husband’s and the wife’s first and last names, if not addressing the wife directly feels outdated or awkward:
Mr. John Smith and Mrs. Bailey Smith or Mr. William and Mrs. Bailey Belcher
Different last names
You can list either the husband’s or the wife’s name first based on your preference, whomever your closest with, or the alphabet.
Mr. William Smith and Mrs. Daisy Jones
Hyphenated name
List the hyphenated name last.
Mr. William Smith and Mrs. Daisy Jones-Smith
One partner is a doctor
List the doctor first regardless of gender.
Dr. Daisy Jones and Mr. William Smith
Both partners are doctors with the same last name
You can address their invite to “The Doctors” or include their first names:
The Doctors Smith or Drs. William and Daisy Smith
Both partners are doctors with different last names
List their names in alphabetical order:
Dr. Daisy Jones and Dr. William Smith
A distinguished title
Other than doctor...such as judge, reverend, military personnel, etc., apply the same rule for doctors.
The Honorable William Smith and Mrs. Daisy Smith or Captains William and Daisy Smith, US Army or Officer William Smith and Mrs. Daisy Smith
Same Sex
The same etiquette applies for same-sex couples as for any other couple, married or unmarried.
Who is invited: A single person
Single female
Use “Ms.” unless she is younger than 18—in that case, use “Miss”
Ms. Daisy Jones or Miss Daisy Jones
Single male
Use “Mr.” unless he is younger than 18—then you don't add a title.
Mr. William Smith
Widow
You should inquire for preference, but typically use:
Mrs. Daisy Jones
Divorced female
Use “Ms.” or “Mrs.” and use her ex husband's last name if she still uses it, or her maiden name.
Mrs./Ms. Daisy Smith Mrs/Ms. Daisy Jones
General Rule
If you are having a very casual wedding (BBQ, brunch...etc.), you can use less formal addressing, and just use first names.