Saku is a masculine Finnish given name. Notable people with the name include:
Saku (written: 佐久) is also a feminine Japanese given name. Notable people with the name include:
- Matsudaira Saku (松平 佐久, 1846–1909), concubine of the Aizu lord Matsudaira Katamori
Saku is also a Sesotho masculine given name. Notable people with the name include:
- Saku Nkoli Saku (born mid 1800s), one of the first settlers of Ha-Khobotle, Lesotho.
- Mpota Saku (born 1908), Mosotho second world war veteran.