圆底烧瓶是实验室中使用的一种烧瓶类玻璃器皿，用来盛液体物质，特别适于加热煮沸液体。

一般的玻璃圆底烧瓶多根据Pyrex规格加入了硼，以增加其耐热性。底部为圆形，有些最底端削平以便于直立。上有一个或多个颈，用来进出容物，以及和其他的实验器皿相连。颈口稍做喇叭状，内面上还经常有磨砂以便和其他玻璃器皿紧密结合。

使用的时候，用夹子将瓶颈固定于实验架台上。左图的蒸馏装置使用了两个圆底烧瓶：(2)为直接受热容器，用本生灯隔嵌有石棉或者陶瓷的金属网加热，以使其受热均匀。(8)为承接馏出液体的容器。

加热也可通过电热垫、水浴等进行。圆底烧瓶也常连接到旋转蒸发器上，经减压加热后可排除挥发性溶液。

A Florence flask is a type of flask used as an item of laboratory glassware. It is used as a container to hold liquids. A Florence flask has a round body, a single long neck, and often a flat bottom. It is designed for uniform heating, boiling, distillation and ease of swirling; it is produced in a number of different glass thicknesses to stand different types of use. They are often made of borosilicate glass for heat and chemical resistance. Traditional Florence flasks typically do not have a ground glass joint on their rather longer necks, but typically have a slight lip or flange around the tip of the neck. A common volume for a Florence flask is 1 litre.