Prince Frederick of Württemberg
Prince" Frederick" Charles Augustus of Württemberg( 21 February 1808 – 9 May 1870) was a General in the Army of Württemberg and the father of William II of Württemberg.
Frederick was a member of the Royal Family of Württemberg and a Prince of Württemberg.
Louis Frederick, Duke of Württemberg-Montbéliard
Louis Frederick of Württemberg- Montbéliard( 29 January 1586 in Montbéliard – 26 January 1631 in Montbéliard) was the founder of a cadet line of the House of Württemberg known as the Dukes of Württemberg- Montbéliard.
Louis Frederick of Württemberg was born at Montbéliard Castle as the fifth child and second son of Duke Frederick I of Württemberg, and princess Sibylla of Anhalt.
Duke Alexander of Württemberg (1771–1833)
Duke Alexander of Württemberg
(Mömpelgard/Montbéliard, then Württemberg (now France), 5 May 1771 – Gotha, Thuringia, Germany, 4 July 1833) was a Duke of Württemberg.
The son of Frederick II Eugene, Duke of Württemberg and of Sophia Dorothea of Brandenburg-Schwedt.
His sister Sophie Dorothea married Tsar Paul I of Russia.
Christoph, Duke of Württemberg
Christoph of Württemberg, Duke of Württemberg (12 May 1515 – 28 December 1568) ruled as Duke of Württemberg from 1550 until his death in 1568.
Duchess Marie of Württemberg
Duchess Marie of Württemberg (Antoinette Friederike Auguste Marie Anna Herzogin von Württemberg; 17 September 1799 – 24 September 1860) was a daughter of Duke Alexander of Württemberg and Antoinette of Saxe-Coburg-Saalfeld.
She was Duchess of Saxe-Coburg and Gotha from 1832 to 1844 as the second wife of Duke Ernest I.
As such, she was the stepmother of Prince Albert, consort of Queen Victoria.
Duke Alexander of Württemberg (1804–1885)
Duke Alexander Paul Ludwig Konstantin of Württemberg( 9 September 1804, Saint Petersburg – 4 July 1885 Tüffer) was the father of Francis, Duke of Teck and the grandfather of Mary of Teck, wife of George V of the United Kingdom.
His father was Duke Louis of Württemberg, brother of King Frederick I of Württemberg and Empress Maria Feodorovna of Russia.
His mother was Princess Henriette of Nassau- Weilburg, a great- granddaughter of George II of Great Britain through his eldest daughter Anne, Princess of Orange.
Duchess Marie-Thérèse of Württemberg
Duchess Marie Thérèse of Württemberg (born 12 November 1934) known as Duchess of Montpensier, is a German-born aristocrat.
A daughter of the claimant to the royal throne of Württemberg, abolished in 1918, she was the first wife of Prince Henri, Count of Clermont.
Duchess Marie Thérèse is the mother of Prince Jean, Duke of Vendôme, head of the House of Orléans and Orléanist claimant to the French throne.
Prince Eudes, Duke of Angoulême
Prince Eudes Thibaut Joseph Marie of Orléans, Duke of Angoulême( born 18 March 1968), is the youngest son of Henri, Count of Paris, Duke of France, the late Orleanist claimant to the throne of France, and of Duchess Marie Therese of Württemberg.
Princess Augusta of Württemberg
Princess Augusta of Württemberg( 4 October 1826 in Stuttgart – 3 December 1898, ibid.) was a daughter of King William I of Württemberg and his wife, Pauline of Württemberg.
Princess Catherine of Württemberg
Princess Catherine Frederica Charlotte of Württemberg (Stuttgart, 24 August 1821 – Stuttgart, 6 December 1898) was a daughter of William I of Württemberg and Pauline Therese of Württemberg.
She was the mother of William II of Württemberg.

Question: Who is Duchess Marie Of Württemberg's paternal grandfather?
Answer: Frederick II Eugene, Duke of Württemberg