The Communist Party of Germany (Opposition) (German: Kommunistische Partei Deutschlands (Opposition)), generally abbreviated as KPO or KPD(O), was a communist opposition organisation established at the end of 1928 and maintaining its existence until 1939 or 1940. After the rise of Adolf Hitler and the Nazi Party to power in January 1933, the KPO existed only as an illegal and underground organization. The group initially sought to modify, later to replace, the mainstream Communist Party of Germany (KPD) headed by Ernst Thälmann. The KPO was the first national section affiliated to the International Communist Opposition (ICO).