Olearia chathamica is a shrub or small tree with quite a rounded habit and is endemic to the windswept, coastal Chatham Islands where it can form dense scrubland communities on the southern tablelands, Pitt, Mangere and South East Islands. It grows on rocky spurs and steep coastal cliffs as well as in open forest that has developed on deep peat. It is also occasionally found in sphagnum bogs or lake-shore scarps and survives best in areas inaccessible to stock. It has large leathery leaves that have toothed margins, a glossy green upper surface and a soft white underside.

Olearia chathamica from October to March produces flowers which are white with purple a centre. At 4cm+ across it is one of the largest flowers of all NZ Olearia.