Cassinia theresae is a species of flowering plant in the family Asteraceae and is endemic to central New South Wales.

It is an erect shrub with hairy young stems, needle-shaped leaves with flared bases, and corymbs of up to fifty flower heads.

Flowering occurs from January to July and the achenes are 0.5–0.8 mm (0.020–0.031 in) long with a pappus of thirteen to twenty-four bristles.

[2] Cassinia theresae was first formally described in 2004 by Anthony Edward Orchard in Australian Systematic Botany from specimens collected between Tottenham and Tullamore in 2004.

[3] Cassinia theresae grows in woodland on plains in south-central New South Wales.