It is probably named after Timothy Hanson, an American farmer and agriculturalist said to have introduced it from New England to the southern states in the early 18th century.

There are two subspecies: Timothy was unintentionally introduced to North America by early settlers, and was first described in 1711 by John Hurd from plants growing in New Hampshire.

Timothy hay is a staple food for domestic pet rabbits, guinea pigs, chinchillas, and degus, often making up the bulk of their diet.

Some caterpillars use it as a food plant, e.g. the Essex skipper (Thymelicus lineola) and the marbled white (Melanargia galathea).

Due to high phenotypic and genetic heterogeneity in individual plants, and the polyploidy of many species, breeding programs for timothy are accompanied by some difficulties.

The spikelets of timothy are twin hornlike projections arranged in cylindrical panicles, whereas foxtail has a soft, single awn.

[19][20] Timothy canary grass (Phalaris angusta), another species with a similar cylindrical panicle, is toxic to livestock.