| Margaret B. Seymour | |
| Office: | Co-General Counsel for the Charleston County School District |
| Term Start: | October 14, 2022 |
| Office1: | Senior Judge of the United States District Court for the District of South Carolina |
| Term Start1: | January 16, 2013 |
| Term End1: | August 31, 2022 |
| Office2: | Chief Judge of the United States District Court for the District of South Carolina |
| Term Start2: | January 3, 2012 |
| Term End2: | January 16, 2013 |
| Predecessor2: | David C. Norton |
| Successor2: | Terry L. Wooten |
| Office3: | Judge of the United States District Court for the District of South Carolina |
| Term Start3: | October 22, 1998 |
| Term End3: | January 16, 2013 |
| Appointer3: | Bill Clinton |
| Predecessor3: | William Byrd Traxler Jr. |
| Successor3: | Bruce Howe Hendricks |
| Office4: | Magistrate Judge of the United States District Court for the District of South Carolina |
| Term Start4: | 1996 |
| Term End4: | 1998 |
| Office5: | United States Attorney for the District of South Carolina Acting |
| Term Start5: | January 1996 |
| Term End5: | May 1996 |
| President5: | Bill Clinton |
| Successor5: | J. Rene Josey |
| Term Start6: | April 1993 |
| Term End6: | May 1993 |
| President6: | Bill Clinton |
| Predecessor6: | John S. Simmons |
| Birth Name: | Margaret Louise Beane Seymour |
| Birth Date: | 16 January 1947 |
| Birth Place: | Washington, D.C., U.S. |
| Spouse: | Joseph D. Shine |
| Education: | Howard University (BA) American University (JD) |
Margaret Louise Beane Seymour (born January 16, 1947) is an American lawyer who is a former United States district judge of the United States District Court for the District of South Carolina.
Born in Washington, D.C., Seymour received a Bachelor of Arts degree from Howard University in 1969 and a Juris Doctor from Washington College of Law at American University in 1977. She was an equal opportunity specialist for the United States Department of Health, Education & Welfare from 1972 to 1979, and for the United States Equal Employment Opportunity Commission from 1979 to 1980. She was an attorney in the Office of Civil Rights of the United States Department of Education from 1980 to 1988. She was in private practice from 1988 to 1990. She was an Assistant United States Attorney of the District of South Carolina from 1990 to 1996, serving as the United States Attorney (interim) for that district from 1993 to 1996.
Seymour was a United States magistrate judge for the United States District Court for the District of South Carolina from 1996 to 1998. On September 9, 1998, Seymour was nominated by President Bill Clinton to a seat on the District of South Carolina vacated by William Byrd Traxler Jr.. She was confirmed by the United States Senate on October 21, 1998, and received her commission on October 22, 1998. On January 3, 2012, she became chief judge, serving as such until she took senior status on January 16, 2013. She retired on August 31, 2022.