Trees, shrubs, herbs, climbers, hemiparasitic mostly on the roots of other plants but sometimes also stem-hemiparasites. Leaves opposite or alternate, rarely whorled, simple, often reduced and scale-like, entire, sometimes caducous and/or apparently absent; stipules absent. Inflorescences axillary or terminal racemes, spikes, panicles, corymbs or cymes, often reduced to a single flower, usually bracteate, sometimes bracteolate. Flowers regular, bisexual or unisexual on monoecious or dioecious plants; perianth of a single whorl of 2–5 valvate segments (tepals) inserted on a shallow cup-like receptacle; stamens as many as tepals and adnate to their bases, the staminal filaments sometimes united, anthers 1- or 2-celled, often lobed and appearing 4-celled; ovary inferior or superior, 1- or imperfectly 2–5-celled, ovules 1 per cell or part-cell, pendulous, style simple, very short, stigma 2–5-lobed. Fruit a drupe or indehiscent nut, mesocarp often fleshy, receptacle often enlarged and fleshy; seed with copious albumen.
About 44 genera with c. 990 species, virtually cosmopolitan, chiefly in tropical and temperate regions; 13 genera and 66 species in Australia. The placement of some genera is controversial. Some authorities recognise Thesiaceae (Thesium) and Viscaceae (Korthalsella, Notothixos) as distinct.