Hadmar I of Kuenring

spelling Hademar; died 27 May 1138) was a German nobleman who served as a ministerialis in the Margraviate of Austria (Ostarrîchi).

While many sources refer to Hadmar as a (great-)grandson of legendary Azzo of Gobatsburg, more recent research has shown this to be incorrect.

[1] He is credited for the construction of Kühnring castle (in present-day Lower Austria), which became the ancestral seat of the Kuenring noble family.

Hadmar also had Dürnstein Castle erected in his Wachau estates, where about sixty years later King Richard I of England was imprisoned after being captured near Vienna by Duke Leopold V of Austria.

The establishment of Zwettl Abbey was confirmed by King Conrad III of Germany and Pope Innocent II in 1139/40.