Eldgjá is a volcanic canyon in Iceland. Eldgjá and the nearby Laki craters are part of the same volcanic system as Katla in the south of the country. Eldgjá means "fire canyon" in Icelandic.

Situated between Landmannalaugar and Kirkjubæjarklaustur, the canyon is at its greatest 270m deep and 600m wide. It was discovered by Þorvaldur Þoroddsen in 1803. The first documented eruption in 934 was the largest flood basalt in historic time. An estimated 18 km³ of lava poured out of the earth.

There is a nice waterfall called Ófærufoss within the canyon. A natural bridge across the waterfall collapsed in 1993.