Frederick Clark Sayles (July 17, 1835 – June 5, 1903) was an American entrepreneur and the first mayor of Pawtucket, Rhode Island in 1885.

[3] After the death of his wife, Sayles donated a plot of land for the construction of a public library in Pawtucket.

The Deborah Cook Sayles Public Library opened in 1902 and is on the National Register of Historic Places.

[4] His daughter, Deborah Wilcox Hill and her husband Fred B Hill, contributed to the construction of the Sayles-Hill men's gymnasium (later turned student center) at Carleton College in Northfield, Minnesota, named in Sayles' honor in 1910.

[5] His other daughter, Caroline M. Sayles, married Frederick William Holls, a lawyer and diplomat who served as the Secretary of the United States Delegation to the Hague Conventions of 1899 and 1907.