血管（英语：blood vessel）是生物运送血液的管道，依运输方向可分为动脉、静脉与微血管。动脉从心脏将血液带至身体组织，静脉将血液自组织间带回心脏，微血管则连接动脉与静脉，是血液与组织间物质交换的主要场所。各种生物拥有的血管型态各不相同：开放式循环（open circulation）生物，如昆虫，只有动脉，血液自动脉流出直接接触身体组织，再由心脏上的开孔回收血液；闭锁式循环（closed circulation）生物，如哺乳类、鸟类、爬虫类、鱼类，则由动脉连接微血管再接至静脉，最后回归心脏。

The blood vessels are the part of the circulatory system that transports blood throughout the human body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart. The word vascular, meaning relating to the blood vessels, is derived from the Latin vas, meaning vessel.