The genus comprises annual and perennial herbaceous plants or (rarely) small shrubs, growing to 10–100 cm tall, with oblong-oval leaves.

Alyssum flowers are characteristically small and grouped in terminal clusters;[1] they are often yellow or white colored but can be pink or purple.

Alyssum foliage is used as food by the caterpillars of certain Lepidoptera, including the Gem (Orthonama obstipata).

The following names are listed by World Flora Online as accepted (as of the end of 2021),[4] but in AlyBase[3] have either been assigned to different genera (typically based on molecular phylogeny studies) or have been reduced to synonymy.

A question mark indicates doubtful synonyms or species names with unresolved taxonomic status.