温室，又称玻璃温室或暖房，是一座专用作种植植物的建筑物。它的建造物料是玻璃或塑料，温室会因太阳发出的电磁辐射而加热，使温室内的植物、泥土、空气等变暖。

玻璃被用作为温室的建造物料是因为它是不同光学频谱的其中一种可选性的传输媒介，而它的另一个作用是可以集中抓住能量，使温室内的植物、空气变暖。这些热空气会下沉于地面和防止上升和流动，因此若果例如在温室屋顶上只打开一个小窗口，温室温度就会显著地下降，这个原理就仿如一个基本的自动排气冷却系统。温室的兴建就是可以抓住电磁辐射和防止对流现象。因此，用于温室的玻璃作为气流屏障，其效果是捕获温室内的能量。靠近地面被加热的空气, 就被防止无限地上升和流失。

A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of transparent material, such as glass, in which plants requiring regulated climatic conditions are grown. These structures range in size from small sheds to industrial-sized buildings. A miniature greenhouse is known as a cold frame. The interior of a greenhouse exposed to sunlight becomes significantly warmer than the external ambient temperature, protecting its contents in cold weather.