kˈævəndˌɪʃ wʌz bˈɔːɹn ɪn wˈɛstmɪnstɚ, ðə θˈɜːd sˈʌn ʌv dʒˈɔːɹdʒ kˈævəndˌɪʃ, fˈɜːst ˈɜːl ʌv bˈɜːlɪŋtən ænd lˈeɪdi ᵻlˈɪzəbəθ kˈɑːmptən, dˈɔːɾɚɹ ænd ˈɛɹɛs ʌvðə sˈɛvənθ ˈɜːl ʌv nɔːɹθˈæmptən.
Cavendish was born in Westminster, the third son of George Cavendish, 1st Earl of Burlington and Lady Elizabeth Compton, daughter and heiress of the 7th Earl of Northampton.