Mieczysław Michałowicz (1876, Saint Petersburg - 1965) was a Polish social and political activist, medical doctor (pediatrics) and professor of the Warsaw University. Freemason.
Activist of Polish Socialist Party. Rector of the Warsaw University from 1930 to 1931. Member of Polish Academy of Skills and Polish Academy of Sciences. Member of Senate of Poland, first supporter of sanacja regime, but later in opposition, one of the co-founders of the Stronnictwo Demokratyczne party. During World War II imprisoned by the Nazis. After the war decided to collaborate with the Polish communist Soviet-backed regime.