Finlayson's squirrel or the variable squirrel (Callosciurus finlaysonii) is a species of rodent in the family Sciuridae. It is found in Cambodia, Laos, Myanmar, Thailand, and Vietnam. It has numerous subspecies that vary greatly in appearance and it occurs in a wide range of wooded habitats, including gardens and parks in cities like Bangkok. It was named in honour of the Scottish naturalist and traveller George Finlayson.
The Finlayson's squirrel has a head-and-body length of about 21–22 cm (8.3–8.7 in) and its tail is about 22–24 cm (8.7–9.4 in) long. There are currently 16 recognised subspecies. Additional subspecies are sometimes recognised. The subspecific name of C. f. boonsongi commemorates Thai zoologist and conservationist Boonsong Lekagul.
The pelage colour in this species is extremely variable and the subspecies are often defined by this feature.