De Zayas' work focuses "inter alia" on the judicial protection of peoples and minorities. He has written and lectured extensively on human rights, including the jurisprudence of the United Nations Human Rights Committee, the Armenian Genocide, the Holocaust, the US-run detention centers at Guantanamo Bay, ethnic cleansing in the former Yugoslavia, the expulsion of Eastern European Germans after the Second World War, the invasion of Cyprus by Turkey in 1974, the rights of minorities, the right to freedom of opinion and expression, and the rights of indigenous peoples.