Saku is a masculine Finnish given name. Notable people with the name include:
- Saku Kinnunen (born 1995), Finnish ice hockey player
- Saku Koivu (born 1974), Finnish ice hockey player
- Saku Mäenalanen (born 1994), Finnish ice hockey player
- Saku Pesonen (born 1985), Finnish footballer
- Saku Puhakainen (born 1975), Finnish footballer
- Saku Salmela (born 1990), Finnish ice hockey player
- Saku Salminen (born 1994), Finnish ice hockey player
- Saku Savolainen (born 1996), Finnish footballer
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.