They are small to medium-sized trees or large shrubs, reaching 5-25 m tall (to 40 m in C. macleayana). The leaves are evergreen and scale-like, except young seedlings, where they are needle-like; in C. macleayana, needle-like leaves are found mixed with scale leaves throughout the tree's life. The scales are arranged in six rows along the twigs, in alternating whorls of three (often in whorls of four in C. macleayana).
The male cones are small, 3-6 mm long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, maturing in 18-20 months to 1-3 cm long and wide, globular to ovoid (acute in C. macleayana), with six overlapping, thick, woody scales, arranged in two whorls of three (often 8 scales in C. macleayana). The cones remain closed on the trees for many years, opening only after being scorched by a bushfire; this then releases the seeds to grow on the newly cleared burnt ground.
The genus is divided into two sections, with the atypical C. macleayana in sect. Octoclinis, and all the other species in sect. Callitris. Some botanists treat C. macleayana in a separate genus, as Octoclinis macleayana. C. macleayana is also distinct in occurring in rainforest on the east coast of Australia; the other species all grow on dry sites.
The closest relatives of Callitris are Actinostrobus from southwest Western Australia, which differs in its cones having several basal whorls of small sterile scales, and Neocallitropsis from New Caledonia, distinct in its needle-like leaves throughout the life of the plant (not just seedlings) and always arranged in whorls of four (not three).
The wood of cypress-pines is light, soft and aromatic. It can be easily split and resists decay. It is used to make furniture, indoor and outdoor panelling, and fence posts. Cypress-pines are occasionally planted as ornamental trees, but their use is restricted by the high risks imposed by their very high flammability in bushfires.