| Ademar Fonseca | |
| Fullname: | Ademar Fonseca Nogueira Júnior |
| Birth Date: | 1963 4, df=yes |
| Manageryears1: | 1995 |
| Managerclubs1: | Brazil Women |
| Manageryears2: | 2006 |
| Managerclubs2: | Venezuela Women |
Ademar Fonseca Nogueira Júnior (17 April 1963 – 8 June 2017), commonly known as Dema, was a Brazilian football manager.
Fonseca was the head coach of the Brazil women's national team at the 1995 FIFA Women's World Cup.