Thesium humifusum is a species of hemiparasitic flowering plant in the family Santalaceae found in western Europe and north-western Africa, known as bastard-toadflax.

[7] In Great Britain, it is restricted to downlands over chalk or oolitic limestone in southern England.

[4] Thesium humifusum usually grows flat along the ground, only occasionally producing more erect flowering stems.

Its leaves are a yellowish green colour and are strap-shaped and up to 25 mm (1 in) long, with a single central vein.

[6][4] Thesium humifusum was first described by Augustin Pyramus de Candolle in the 1815 third edition of his Flore Française.