Mary Seymour was the daughter of Katherine Parr, queen dowager of England and Thomas Seymour, Baron Seymour of Sudeley and uncle to Edward VI.
Mary Seymour may also refer to:
- Mary Somerset, Duchess of Beaufort (gardener) (1630âÂÂ1715), married name Mary Seymour
- Mary Seymour, Duchess of Somerset (1697âÂÂ1768)
- Mary Seymour, Marchioness of Hertford (1846âÂÂ1909)
- Mary Foot Seymour (1846âÂÂ1893), American writer
- Mary Townsend Seymour (1873âÂÂ1957), American politician
- Mary Alice Seymour (1837âÂÂ1897), American musician, author, elocutionist, and critic
- Mary Seymour (died 1886), wife of Horatio Seymour and First Lady of New York