In Weimar on 26 May 1555 John Frederick II married his first wife, Agnes of Hesse, Dowager Electress of Saxony.
Six months later she suffered a miscarriage and died, on 4 November 1555.

In Weimar on 12 June 1558 John Frederick II married his second wife, Countess Palatine Elisabeth of Simmern-Sponheim, daughter of the later (1559) Frederick III, Elector Palatine.
They had four sons:
John Frederick (30 November 1559, Weimar – 8 August 1560, Weimar)
Frederick Henry (3 February 1563, Heldburg – 4 August 1572, Eisenberg)
John Casimir, Duke of Saxe-Coburg (12 June 1564, Gotha – 16 July 1633, Coburg)
John Ernest, Duke of Saxe-Eisenach (9 July 1566, Gotha – 23 October 1638, Eisenach)
In Weimar on 26 May 1555 John Frederick II married his first wife, Agnes of Hesse, Dowager Electress of Saxony. Six months later she suffered a miscarriage and died, on 4 November 1555.
In Weimar on 12 June 1558 John Frederick II married his second wife, Countess Palatine Elisabeth of Simmern-Sponheim, daughter of the later (1559) Frederick III, Elector Palatine. They had four sons:
John Frederick (30 November 1559, Weimar – 8 August 1560, Weimar)
Frederick Henry (3 February 1563, Heldburg – 4 August 1572, Eisenberg)
John Casimir, Duke of Saxe-Coburg (12 June 1564, Gotha – 16 July 1633, Coburg)
John Ernest, Duke of Saxe-Eisenach (9 July 1566, Gotha – 23 October 1638, Eisenach)
John Frederick II, Duke of Saxony