Phyllis McAlpin Stewart Schlafly (b. August 15, 1924, in St. Louis, Missouri; pronounced /ˈfɪlɪs ˈʃlæfli/) is an American conservative political activist and constitutional attorney known for her opposition to feminism and the Equal Rights Amendment. Her bestselling book, A Choice, Not An Echo, was published in 1964 from her home in Alton, Illinois, across the Mississippi River from her native St. Louis. From this self-publication, she formed her Pere Marquette Publishers company. A Choice, Not an Echo decries the power of the secret kingmakers and persuaders that once included New York Governors Thomas E. Dewey and Nelson A. Rockefeller. Schlafly supported U.S. Senator Barry M. Goldwater in his unsuccessful race against President Lyndon B. Johnson. She has co-authored several books on national defense and was highly critical of arms-control agreements with the former Soviet Union.

Schlafly also maintains an active presence on the lecture circuit. In 1972, she founded the Eagle Forum, and was the founder and president of a sister organization known as the Eagle Forum Education & Legal Defense Fund, which also operates in the Eagle Forum's St. Louis office. As of 2009, she is still the president of both organizations. Since 1967, she has published her own political newsletter, the Phyllis Schlafly Report.

Schlafly's great-grandfather Stewart, a Presbyterian, came from Scotland to New York, in 1851, and moved westward through Canada before settling in Michigan. Her grandfather, Andrew F. Stewart, was a successful master mechanic with the Chesapeake & Ohio Railway. Schlafly's father, John Bruce Stewart, was a machinist and salesman of industrial equipment, principally for Westinghouse. He became unemployed in 1932 during the Great Depression and could not find permanent work until World War II. He was granted a patent in 1944 for a rotary engine.