Roubiliac was largely employed for portrait statues and busts, and especially for sepulchral monuments. His chief works in Westminster Abbey are the monuments of Handel, Admiral Warren, Marshal Wade, Mrs Nightingale and the Duke of Argyll, the last of these being the first work which established Roubiliac's fame as a sculptor. The statues of George I, Sir Isaac Newton, and the Duke of Somerset at Cambridge, and of George II erected in Golden Square, London, were also his work. Trinity College, Cambridge, possesses a series of busts of distinguished members of the college by him.
Roubiliac possessed skill in portraiture and was technically a master, but lived at a time when his art had sunk to a low ebb. His figures are frequently uneasy, devoid of dignity and sculpturesque breadth, and his draperies treated in a manner more suited to painting than sculpture. There are, however, noteworthy exceptions, his bust of Pope, for example, reaching a high standard. More often, however, his striving after dramatic effect detracts from repose of attitude.
His most celebrated work, the Nightingale monument, in Westminster Abbey, a marvel of technical skill, is saved from being ludicrous by its ghastly and even impressive hideousness. On this the dying wife is represented as sinking in the arms of her husband, who in vain strives to ward off a dart which Death is aiming at her. The lower part of the monument, on which the two portrait figures stand, is shaped like a tomb, out of the opening door of which Death, as a half-veiled skeleton, is bursting forth. The celebrated bust of Shakespeare, known as the Davenant bust, in the possession of the Garrick Club, London, must be attributed to Roubiliac. The statue of Shakespeare, a commission from David Garrick, and bequeathed by the actor to the English nation, is in the British Museum, and shows the talent of the sculptor in a flattering light. He was also commissioned by Jonathan Tyers to make a sculpture of Handel for his pleasure gardens at Vauxhall. It is noteworthy that none of his work is recorded in France, the land of his birth and education.