Grass refers to the many species of plants in the family Poaceae.

Grass may also refer to:

• Grass is also commonly used in the names of other plants, some but not all with narrow leaves, including:
  • Blue-eyed grasses, Sisyrinchium in the family Iridaceae
  • China grass, Boehmeria nivea, a nettle grown for fibre, in family Urticaceae
  • Cotton grass, Eriophorum spp., in family Cyperaceae.
  • Deergrass (disambiguation):
    • Rhexia spp., in family Melastomataceae
    • Trichophorum spp., in family Cyperaceae, particularly Trichophorum cespitosum
  • Ditch grass, Ruppia maritima, in family Ruppiaceae
  • Eelgrass:
    • Zostera in family Zosteraceae
    • Vallisneria in family Hydrocharitaceae
  • Golden-eye grass, Curculigo orchioides, in family Hypoxidaceae
  • Good Friday Grass, Luzula campestris, in family Juncaceae.
  • Goosegrass, Galium aparine in the family Rubiaceae
  • Grass (cannabis), a slang name for cannabis (drug)
  • Grass of Parnassus, Parnassia, in family Celastraceae
  • Knotgrass, Polygonum spp., in family Polygonaceae
  • Mondo grass, Ophiopogon japonicus, in family Asparagaceae
  • Nutgrass, Cyperus rotundus, in family Cyperaceae
  • Pepper grass, Lepidium spp., in family Brassicaceae
  • Sawgrass, Cladium spp., in family Cyperaceae
  • Scurvy-grass, Cochlearia spp., in family Brassicaceae
  • Scurvy-grass sorrel, Oxalis enneaphylla in family Oxalidaceae
  • Seagrasses in four families, Posidoniaceae, Zosteraceae, Hydrocharitaceae, or Cymodoceaceae
  • Sleeping grass, Mimosa pudica, in family Fabaceae
  • Whitlow grass, Draba and Erophila spp., in family Brassicaceae:
  • Xyridaceae, known as the yellow-eyed grass family

• Alex Grass (1927–2009), American businessman and lawyer
• Arthur Grass (1897–1994), English-born Brazilian cricketer
• Frank J. Grass (born 1951), American general
• Günter Grass (1927–2015), German author and playwright, Nobel Prize in Literature 1999
• John Grass (1837–1918), Native American Lakota leader
• Philippe Grass (1801–1876), French sculptor
• Vincent Grass (born 1949), Belgian actor

• Grass Mountain (Vermont)
• Grass Range, Montana
• Grass Valley, California

• Grass (1925 film), a documentary about the Bakhtiari tribe of Iran
• Grass (1999 film), a documentary about marijuana
• Grass (1968), an independent film by Clarke Mackey
• Grass (2018 film), a South Korean film

• Grass (card game), a cannabis-themed card game similar to Mille Bornes

• Grass (novel), a novel in The Arbai Trilogy by Sheri Tepper
• "Grass", a poem by Patti Smith from her 1978 book Babel
• "Grass", a poem by Carl Sandburg

• "Grass", Russian art song by Aleksandr Yegorovich Varlamov (1801–1848)
• Grass (album), a 2005 album by Keller Williams
• "Grass" (Animal Collective song), a single by the band Animal Collective
• "Grass" (XTC song), a 1986 single by XTC, written Moulding, from the Skylarking album
• "Grass" (Robert Wyatt song) single, words by poet Ivor Cutler 1981

• Grass (TV series), a 2003 BBC television series

• GRASS (programming language), a programming language used for animations
• GRASS GIS, a geographic information system
• Gradient Recall Acquisition using Steady States, a form of magnetic resonance imaging

• Grass, grasser or Supergrass (informant) in the UK, an informant, especially one criminal informing on another, to the police or other authorities.
• Grass, an informal name for marijuana.

• Grass dance, a Native American style of pow wow dancing

• Gras (disambiguation)
• Grasse, a commune in the Alpes-Maritimes department (of which it is a sub-prefecture), on the French Riviera