习见蓼（学名：Polygonum plebeium）为蓼科蓼属下的一个种。

Polygonum plebeium, the common knotweed, is a species of flowering plant in the knotweed family, found natively throughout much of South Asia and in Madagascar, and introduced to the United States and Australia. It occurs in disturbed habitats that frequently are flooded, such as banks, ditches, and rice fields. It is used as a vegetable in food in some locations.