Friedrich "Fritz" Demmer (17 April 1911 - date of death unknown) was an Austrian ice hockey player who competed for the Austrian national team at the 1936 Winter Olympics in Garmisch-Partenkirchen and the 1948 Winter Olympics in Saint-Moritz.
Demmer played 12 games at the two Olympics, scoring a total of six goals.
He also made 54 appearances for the Austrian national team at the World Championships between 1930 and 1949.
Demmer was a top offensive threat on the team, scoring 31 goals in his World Championship career.
He played club hockey for Wiener EV in the Austrian Hockey Championship.