The Crimson Rosella is a beautiful parrot native to eastern and south eastern Australia. It is commonly found in, but not restricted to, mountain forests and suburban gardens.

Adults and juveniles generally show strikingly different colouration in south-eastern populations, with predominantly greenish-olive body plumage on the juvenile, most persistent on the nape and breast. Juveniles are said to 'ripen' as they get older and turn from green to red. All races have blue cheeks and black-scalloped blue-marginned wings and predominantly blue tail with predominantly red coloration. The Crimson Rosella’s blue tail feathers are one of the favourite decorations of the Satin Bowerbird. The bill is pale grey and the iris dark brown.

There is very little sexual dimorphism in Crimson Rosellas. The most noticeable difference between genders is that males are up to 15% larger, and have a relatively larger and wider beak.

The Crimson Rosella occurs from southeastern South Australia, through Tasmania, Victoria and coastal New South Wales into Southeastern Queensland. A disparate population occurs in North Queensland.

It is common in coastal and mountain forests at all altitudes. It primarily lives in forests and woodlands, preferring older and wetter forests. They can be found in tropical, subtropical, and temperate rainforests, both wet and dry sclerophyllous forests, riparian forests, and woodlands, all the way from sea-level up to the tree-line. They will also live in human-affected areas such as farmlands, pastures, fire-breaks, parks, reserves, gardens, and golf-courses. They are rarely found in treeless areas. At night, they roost on high tree branches.

Almost all Rosellas are sedentary, although occasional populations are considered nomadic; no Rosellas are migratory. Outside of the breeding season, Crimson Rosellas tend to congregate in pairs or small groups and feeding parties. The largest groups are usually composed of juveniles, who will gather in flocks of up to 20 individuals. When they forage, they are conspicuous and chatter noisily. Rosellas are monogamous, and during the breeding season, adult birds will not congregate in groups and will only forage with their mate.