The Lewin's Honeyeater is small to medium in size. It is dark greenish grey in colour, with a creamy yellow gape (fleshy corners of the mouth). It has large, yellowish crescent-shaped ear patches. In flight, the pale yellow edges of the flight feathers can be seen. The bill is black and the eye is blue-grey. Both sexes are similar in appearance. Young Lewin's Honeyeaters are similar to the adults, but have brown eyes.
The overall size and distinctive voice of Lewin's Honeyeater, as well as the shape and size of its ear patch, will identify it from most other honeyeaters. There are two similarly ear-patched but smaller species whose ranges overlap with the Lewin's Honeyeater only in north-eastern Queensland: Yellow-spotted Honeyeater, M. notata, and the Graceful Honeyeater, M. gracilis.
Lewin's Honeyeater prefers the wetter parts of eastern Australia, from northern Queensland to central Victoria.
Lewin's Honeyeater is found in both rainforest and wet sclerophyll forest, and often wanders into more open woodland. It is a common bird, and its call is often heard in these areas.
Sedentary; some altitudinal migration to lower areas in winter.
Lewin's Honeyeaters feed mostly on fruits, favouring berries and small fruits, but also eat insects and nectar. Birds are normally seen alone, but may form loose groups of up to 10 birds. They feed in the upper branches and on the trunks of trees. Some insects are caught in flight.
The nest is a large cup of vegetation and other materials, bound together with spider web and lined with soft material. The eggs are oval in shape. It is unclear what roles each parent performs in nest building and incubation, but both care for the young birds.