Ekstremfjorden is a fjord at the northern coast of Nordaustlandet, Svalbard, east of Laponiahalvøya. It mouths into the western part of Nordenskiöldbukta.
Coordinates: 80°24′19″N 20°05′34″E / 80.4053°N 20.0927°E / 80.4053; 20.0927