Szybowcowy Zakład Doświadczalny (SZD) Glider Experimental Works was a glider design and research centre of the Polish aerospace industry after World War II located in Bielsko-Biała. Through its history it underwent many organizational and name changes among others in 1946-1948 it was Instytut Szybownictwa. After 1969 it existed under other names but an abbreviation SZD continued to be used on designs.