Stora Alvaret (Swedish: [ˈstûːra ˈâlːvarɛt]; "the Great Alvar") is an alvar, a barren limestone terrace, in the southern half of the island of Öland, Sweden. Stora Alvaret is a dagger shaped expanse almost 40 kilometres (25 mi) long and about 10 kilometres (6 mi) at the widest north end. The area of this formation exceeds 260 square kilometres (100 sq mi), making it the largest such expanse in Europe and comprising over one fourth of the land area of the island.

Because of the thin soil mantle and high pH levels, a great assortment of vegetation is found including numerous rare species. Stora Alvaret is not devoid of trees, contrary to a common misconception; in fact, it holds a variety of sparse stunted trees akin to a pygmy forest.

Stora Alvaret falls within UNESCO's Agricultural Landscape of Southern Öland, 56,323 hectares (217.46 sq mi), which was designated World Heritage Site due to its extraordinary prehistory.