Mather Brown (baptized 11 October 1761 – 25 May 1831) was an American painter who was born in Boston, Massachusetts and was active in England.

He arrived in London in 1781 to further his training in Benjamin West's studio, entered the Royal Academy schools in 1782 with plans to be a miniature painter, and began to exhibit a year later.

His first successes were with American sitters, among others his patron John Adams and family in 1784–85; this painting is now in the Boston Athenæum.

A falling off patronage in the mid-1790s, and failure to be elected to the Royal Academy, led Brown to leave London in 1808 for Bath, Bristol, and Liverpool.

He settled in Manchester, returning to London almost two decades later, in 1824, where, even after West's death, he continued to imitate his teacher's style of painting.