Senegalia thomasii is a species within the family Fabaceae[1] that grows as a straggling shrub or tree.

The species is a shrub or small tree that grows up to 12 m tall, its branches are elongated and straight or virgately branched, young branches are commonly grayish in color and are densely pubescent.

[3] It has prickles in threes that are usually blackish and slightly below the nodes, prickles can be up to 7.5 mm long.

[2] Leaves: 1–2 pairs of pinnae, 7–15 leaflets per pinnae, leaf outline is oblong; petiole is up to 2 cm long and rachis is up to 8 cm long.

[3] Fruits are brown to yellowish brown pods containing circular to lenticular shaped seeds.