Eva Catharina König née Hahn (22 March 1736 - 10 January 1778) was a German woman letter writer.

The couple had four children: Maria Amalie Henneberg, Theodor, Engelbert, and Fritz.

During their engagement, Eva made several visits to Vienna to settle her late husband’s estate.

As a result, the couple's mode of contact during their engagement was through written correspondence, most of which has survived.

Eva died in 1778 at the age of 41 of neonatal sepsis soon after the birth of their son Traugott Lessing.