甜茅属（学名：Glyceria）是禾本科下的一个属，通常为多年生水生或泽生草本植物。该属共有约40种，分布于温带地区。

Glyceria is a widespread genus of grass family common across Eurasia, Australia, North Africa, and the Americas.

Glyceria is known commonly as mannagrass in the USA, or, in the UK, sweet-grass. These are perennial rhizomatous grasses found in wet areas in temperate regions worldwide. The base of the grass grows along the ground and may root at several places. Then it grows erect and bears leaf blades which may be flat or folded. The panicle inflorescences nod when heavy. Some mannagrasses are considered weeds while others are endangered in their native habitats.