Seth Merrill Gates (October 16, 1800 – August 24, 1877) was an American merchant, attorney and politician.

He attended the common schools and Middlebury Academy located in the village of Wyoming, New York, before working as a teacher.

He became inspector of the common schools, and in 1825, he served as the deputy sheriff of Le Roy, New York.

Due to his pronounced hostility to slavery, a southern planter offered $500 for his apprehension.

His home, the Seth M. Gates House, at Warsaw, New York, was listed on the National Register of Historic Places in 1992.