A kolač (also spelled kolach, kolace or kolacky , from the Czech and Slovak plural koláče, sg. koláč, diminutive koláčky, meaning "cake/pie") is a type of sweet pastry that holds a portion of fruit surrounded by puffy dough. It is made from yeast dough and common flavors include quark, a dairy product, tvaroh spread, fruit jam and poppy seeds mixed with powidl (povidla).

Originating as a semisweet pastry from Central Europe, they have also become popular in parts of the United States. The name originates from the Czech (Bohemian), and originally Old Slavonic word kolo meaning "circle", "wheel".

In the Czech Republic, a small circular pastry is most often referred to as a Kolač, which has a sweet filling in its center (poppy seed, cottage cheese, nut, marmalade, etc.) Traditional Czech Kolače are used in villages during feasts as a festive treat or at important events (e.g. weddings). They are usually small with a diameter of no more than 8 cm and with only one type of filling and sprinkled with sweet crumb or sugar. They are baked from yeast dough.

In Moravia, large circular Kolače are most often served. In some areas, they have regional names, for example in Wallachia they bake so-called frgály, approximately 25 centimeters in diameter. They are made of yeast dough and are most often filled with jam from apples, pears or plums.

In southern and western Bohemia (especially in the Chod region), Kolače are also large in diameter and decorated with contrasting ornaments, most often made of plum jam, poppy seeds and cottage cheese. They are served cut into triangles similar to pizza.

In some parts of the US, klobásník, which contains sausage, a hot dog, or other meat, is also called kolach because the same dough is used. Unlike kolache, which came to the United States with Czech immigrants, klobásníky were first made by Czechs who settled in Texas. In contrast, Czech koláč is always sweet.

Kolache are often associated with small towns in the midwestern United States where they were introduced by Czech immigrants. They are served at church suppers and on holidays but also as an everyday comfort food. Recipes are usually passed down with some including spices like mace or nutmeg. They can be filled with a combination of prune, apricot, cream cheese, poppy seed or assorted other fillings.