Johanna II. (* 1 April 1948 at Schloss Klagenfurt, Firmar, born as Johanna Isabel Alexandra von Scharnwart-Firmar) was the eldest daughter of Duchess Johanna I Georgina of Rhöntal and Johannes Theodor von Seidlingen-Renmark). She is the Duchess and thereby head of state of Rhöntal. As Duchess she is mostly neutral towards politics.
She was proclaimed as Duchess by the Accession Council on 18 February 2007 the day after her mother Johanna I. Georgina died. Her official coronation was held 5 months later on 2 July 2007 in Firmar cathedral. Johanna married Johann Georg von Scharnwart-Norngau in 1968. They have four children and six grandchildren.
Johanna was born at Schloss Klagenfurt the family seat of the dukes of Rhöntal just outside of Firmar. Her mother was Duchess Johanna I Georgina of Rhöntal and her father Johannes Theodor von Seidlingen-Renmark, Count of Seidlingen eldest son of then Chancellor [[Rainer von Seidlingen-Renmark, Margrave of the Renmark] and his wife Marie. Who was the daughter of hereditary stadtholder of Rhöntal Johann VI. Alexander, 4th Prince of Saargau and his wife Johanna Marie Valentina von Scharnwart-Henrichenburg.
Johanna was baptised in the music room of Schloss Klagenfurt im Musikzimmer des Schloss Klagenfurt by the Archbishop of Firmar Radolf von Humbert. Her godparents were His Royal Highness the Landgrave of Groten-Redlingen, His Royal Highness the Prince of Norngau and Their Royal Highnesses the Duke and Duchess of Grotenburg.
As a daughter of the monarch of Rhöntal Johanna had the title of a Princess of Rhöntal with the style of Royal Highness. Her formal title was Her Royal Highness The Princess Johanna of Rhöntal. At the time of her birth she was first in line of succession replacing her first cousin thrice removed the Landgrave of Groten-Redlingen who had held that position since her mothers accession. Although her birth was widely noticed by the public she was never expected to become Duchess.