The species of Lamiaceae are mainly herbs or shrubs of various sizes, rarely trees. Life cycles of the herbaceous members may be annular or perennial. The stems are usually square, especially when young, and erect or procumbent (lying on the ground). The leaves are opposite or whorled, decussate (in opposite pairs, with each pair at right angles to the one above and below it), and gland-dotted. The leaves are often strongly aromatic due to ethereal oils located in the glandular hairs. The leaf blades are simple, rarely pinnately lobed (Teucrium) or digitately compound (Cedronella, Vitex), with entire or toothed margins. The flowers are arranged in compact axillary cymes (verticillasters), e.g. in the white Leonotis, or are sometimes single in the axils of the leaves.

Sometimes the inflorescences are congested as in Pycnostachys.

The calyces are usually persistent with 5 teeth or lobes. Zygomorphic (irregular) flowers are very characteristic of the family. However, actinomorphic (regular) 4-or 5-lobed flowers occur in some genera. The corolla is tubular and typically 2-lipped (bilabiate) with a 2-lobed upper lip and a 3-lobed lower lip, variously coloured and often hairy. The flowers are bisexual, rarely unisexual. The stamens are usually 4 (2 long and 2 short), arising at the corolla mouth or in the tube, and characteristically exserted from the corolla tube (Hemizygia). 

Sometimes the filaments are connate (cannot be separated). A superior ovary seated on an entire or lobed disc is characteristic, with the style gynobasic (arising from the base of the pistil) or terminal.

The fruits are composed of 4, or by abortion fewer, dry, 1-seeded nutlets, or may be a drupe with 1-4 pyrenes, subtended by or enclosed within a persistent calyx. The outer surface of the nutlets may be smooth or rugose (wrinkled). Occasionally the nutlets are winged (Tinnea).