When writing a letter, what form do I use to address a woman? When writing to a married woman, follow her preference for first and last names if you know it. She may prefer to be addressed by her original name (Ms. Joan L. Conroy). If you do know that she is using her husband’s last name, continue to use her own first name and middle initial (Mrs. Joan L. Noonan).
The form that uses her husband’s first name and middle initial as well (Mrs. James W. Noonan) is acceptable only for social purposes. It should never be used when addressing a business letter to a married woman, and it should not be used when a married woman becomes a widow unless she indicates that this is her preference.
In selecting Ms., Mrs., or Miss, always respect the woman’s preference. If it is not known, use the title “Ms” or omit the courtesy title altogether. Kelly, the examples Gregg gives are “Dear Ms. Noonan” or “Dear Joan Noonan.” I vote for “Ms.” if you don’t know her preference, and it’s business-related.
In the strictest sense of the word, socially, says long-dead and dearly beloved Emily Post, use Mrs. James W. Noonan.