Marcel Fischbach (22 August 1914 – 27 June 1980) was a Luxembourgish politician, journalist, and diplomat. He held the position of Minister for Defence in the second cabinet of Pierre Werner.
From 1939, he wrote for d'Wort, a daily newspaper. After the Second World War, Fischbach sat in both the Chamber of Deputies (1945 – 1958 and 1959 – 1964) and Luxembourg City's Luxembourg communal council (1945 – 1964). On 15 July 1964, he became Minister for Defence. During this time, Fischbach was responsible for the reduction of national service from nine months to six months. However, a political crisis erupted in late 1966 over the final transformation of the Luxembourgian army into an all-volunteer force, over which Fischbach resigned from the cabinet, and retired from politics, on 3 January 1967.
After his resignation, Fischbach became a senior diplomat, serving as Ambassador to Austria (1967 – 1973), Ambassador to Belgium (1973 – 1977), and Ambassador to Germany (1977 – 1979).
Marcel's son, Marc Fischbach, would also go on to serve as Minister for Defence (1984 – 1989).