Robert married Sybil Marcia Graham in 1880. Sybil (daughter of Sir Frederick Ulric Graham, 3rd Baronet of Netherby) was born in 1857; died in 1887. [Group Sheet] [Family Chart]

1. Lady Annabel Crewe-Milnes was born in 1881; died in 1948.
2. Honourable Richard Charles Rodes Crewe-Milnes was born in 1882; died in 1890.
3. Lady Celia Hermoine Crewe-Milnes was born in 1884; died in 1985.
4. Lady Helen Cynthia Crewe-Milnes was born in 1884; died in 1968.

Robert married Lady Margaret Etrenne Hannah Primrose in 1899. Margaret was born in 1881; and died. [Group Sheet] [Family Chart]

1. Lady Mary Evelyn Hungerford Crewe-Milnes was born in 1915; died in 2014.