Blok Mniejszości Narodowych (Polish pronunciation: [ˈblɔɡ mɲɛjˈʂɔɕtɕi narɔˈdɔvɨx], "Bloc of National Minorities") (BMN), was a political party in the Second Polish Republic, representing a coalition of various ethnic minorities in Poland, primarily Ukrainians, Belarusians, Jews and Germans. The Bloc was co-founded by Yitzhak Gruenbaum, a Polish-Jewish politician. BMN took part in the Polish legislative election, 1922, Polish legislative election, 1928 and Polish legislative election, 1930, doing very well in the 1922 elections (19.5% and the second largest party) and '28 elections (14% and the third largest party). In 1930 elections which were considered not free, it fared poorly (3% and the ninth largest party). In the political shakedown following the 1930 elections, the Bloc was dissolved.
In the Second Polish Republic, ethnic minorities constituted 1/3 of total population.