The Morteratsch Glacier (Romansh: Vadret da Morteratsch) is the largest glacier by area in the Bernina Range of the Bündner Alps in Switzerland.

By area and by volume (1.2 km3), it is the third largest glacier in the Eastern Alps, after the Pasterze Glacier and Gepatschferner . The Morteratsch Glacier is a typical valley glacier with a pronounced ice front. The accumulation zone lies between the peaks of Piz Morteratsch , Piz Bernina , Crast' Agüzza , Piz Argient , Piz Zupò and Bellavista. From Piz Argient to the ice front in the Val Morteratsch, its horizontal extent is less than ~6 km (3.7 mi), with an altitude difference of up to 2,000 m (6,600 ft).

Together with the Pers Glacier, originating at Piz Palü , which joins the Morteratsch just below the rock formation Isla Persa ("Lost Isle"), as of 1973 it covered an area of about 16 km2 (6.2 sq mi).