Prince Hieronim Mikołaj Radziwiłł (6 January 1885 – 6 April 1945) was a Polish nobleman, landlord in Balice.

He was a son of Prince Dominik Maria Radziwiłł (1852–1938) and Doña María Dolores de Agramonte y Zayas-Zamudio (1854–1920).

In between the World Wars, he was primarily involved in agriculture, breeding and forestry on his Balice estate which had been built by his father.

During World War II, he was involved in the underground activity of the "Uprawa" gentry organization, which provided funding and food for the Home Army.

Upon her marriage to Prince Radziwiłł in 1909, she renounced her titles as Archduchess of Austria and Princess of Bohemia, Hungary, and Tuscany.

1956), who married Sicilian aristocrat Don Antonio Moncada, Nobile dei Principi of Paternò in 1987, and Princess Lyda Radziwiłł (b.