Sweet grass or sweetgrass may refer to:

• Hierochloe odorata (sweet grass or holy grass), from northern North America and Eurasia
• Sweet-grass or mannagrass, any of the many species in the genus Glyceria
• Anthoxanthum odoratum, Sweet vernal grass, native to Eurasia
• Muhlenbergia sericea, synonym Muhlenbergia filipes, native to the southeastern United States
• colloquially for Cannabis, a psychoactive plant
• Sheath grass belongs to the genus Coleanthus in the sweet grass family

• Sweet Grass, Montana, United States
• Sweet Grass County, Montana, United States
• Sweet Grass Creek, Montana, United States
• Sweet Grass Hills, Montana, United States
• Sweet Grass, Edmonton, Canada
• Sweetgrass First Nation, Saskatchewan, Canada

• Sweet Grass (Cree chief) (1815–1877)
• Sweetgrass (film), a 2009 documentary