| Position: | Defence |
| Shoots: | Left |
| Height Ft: | 5 |
| Height In: | 8 |
| Weight Lb: | 145 |
| Ntl Team: | CAN |
| Birth Date: | 24 March 1896 |
| Birth Place: | Montreal, Quebec, Canada |
| Death Place: | Montreal, Quebec, Canada |
| Career Start: | 1915 |
| Career End: | 1933 |
Cyril Seely "Sig" Slater (March 24, 1896 – October 26, 1969) was a Canadian ice hockey player who competed in the 1924 Winter Olympics. He was born in Montreal.
Slater was a member of the Toronto Granites team that won a gold medal for Canada in ice hockey at the 1924 Winter Olympics.