Mary Margaret Truman Daniel (February 17, 1924 – January 29, 2008) was an American classical soprano, actress, journalist, radio and television personality, writer, and New York socialite. She was the only child of President Harry S. Truman and First Lady Bess Truman. While her father was president during the years 1945 to 1953, Margaret regularly accompanied him on campaign trips, such as the 1948 countrywide whistle-stop campaign lasting several weeks. She also appeared at important White House and political events during those years and was a favorite with the media.

After graduating from George Washington University in 1946, Truman embarked on a career as a coloratura soprano, beginning with a concert appearance with the Detroit Symphony Orchestra in 1947. She appeared in the US in concerts with orchestras and in recitals through 1956. She made recordings for RCA Victor and made television appearances on programs such as What's My Line? and The Bell Telephone Hour.

In 1957, one year after her marriage, Truman abandoned her singing career to pursue a career as a journalist and radio personality when she became the cohost of the program Weekday with Mike Wallace. She also wrote articles as an independent journalist for a variety of publications in the 1960s and 1970s. Truman later became the successful author of a series of murder mysteries as well as a number of works on first ladies their families, including well-received biographies of her father.

Truman was married to journalist Clifton Daniel, managing editor of The New York Times. The couple had four sons and lived in a Park Avenue apartment.