He married Marianna Hildyard, also a barrister, in 1985. She became a QC in 2002. Her father, Sir David Henry Thoroton Hildyard, was the British Ambassador to Chile. They have four children: Hamish, William "Rocco", Rosie and Johnny. Falconer placed his three sons at independent Westminster School and St Paul's School, and his daughter at South Hampstead School. In the lead-up to the 1997 election, as he attempted to be selected for the seat of Dudley East, it proved to be an electoral problem for Falconer. He intended to keep his children at Westminster if selected, which caused the local selection panel to drop him from the selection procedure.