Ilona Lantos (née Grosser) was a Hungarian Jewish homemaker born in Hungary, likely in the early 20th century. She married Tibor Lantos, a banker, and they resided in Budapest, where they raised their only child, Thomas Peter Lantos (later known as Tom Lantos), born on February 1, 1928. As a devoted mother, Ilona managed the household during a time of rising antisemitism in interwar Hungary, providing a stable environment for her son amid economic and political turmoil.

During World War II, the Nazi occupation of Hungary in 1944 brought devastation to the Lantos family. Ilona and her husband were arrested by members of the Arrow Cross Party, a fascist militia allied with the Nazis. In November 1944, they were murdered, with historical accounts indicating they were likely executed by being shot into the Danube River, a common method used by the Arrow Cross for killing Jews. Their son Tom survived the Holocaust by going into hiding with the help of a non-Jewish family and was liberated by Allied forces in 1945.

Ilona's tragic death left a lasting impact on her son, who immigrated to the United States in 1947 and later became a U.S. Congressman known for his advocacy on human rights, Holocaust education, and international justice. Her story is preserved through Tom's memoirs and public testimonies, highlighting the personal toll of the Holocaust on Hungarian Jewish families.