Vicia graminea is a species of flowering plant in the vetch genus Vicia, family Fabaceae. It is native to South America, where it has a meandering distribution in Colombia, Peru, Bolivia, Paraguay, northeast Argentina, southern Brazil, Uruguay, and southern Chile. It is the source for a lectin that is used to identify the N blood group antigen.

Subtaxa: The following subtaxa are accepted:

• Vicia graminea var. graminea – entire range
• Vicia graminea var. nigricarpa – southern Brazil
• Vicia graminea var. transiens – northeast Argentina, Uruguay