Dag Tønder (27 June 1907–13 July 1989) was a Norwegian editor, lawyer, and public official.
Dag Tønder was born on 27 June 1907 in Sjøvegan in Salangen Municipality in Troms county, Norway.
On 18 April 1935, he married Rikarda Johanne Mathisen at the Trondenes Church.
His family name comes from his ancestors who came from the village of Tønder in southern Denmark.
During his time as acting governor, Tønder was helped found the Sámi language newspaper company Ságat.