Least pygmy squirrel

{{Short description|Species of rodent}}

{{Speciesbox

| name = Least pygmy squirrel

| image = Plain pygmy-squirrel (Exilisciurus exilis), Sabah, Borneo, Malaysia.jpg

| image2 = Least (or Plain) Pygmy Squirrel (13970675170).jpg

| status = DD

| status_system = IUCN3.1

| status_ref = {{cite iucn |author=Koprowski, J. |author2=Meijaard, E. |year=2016 |errata=2017 |title=Exilisciurus exilis |volume=2016 |page=e.T8437A115087769 |doi=10.2305/IUCN.UK.2016-3.RLTS.T8437A22244965.en |access-date=10 March 2025}}

| genus = Exilisciurus

| species = exilis

| authority = (S. Müller, 1838)

| synonyms =

}}

The least pygmy squirrel (Exilisciurus exilis), also known as the plain pygmy squirrel, is a species of rodent in the family Sciuridae.{{MSW3 Sciuridae |id=12400564}} This plain olive-brown squirrel is endemic to forests, mostly below an altitude of {{cvt|750|m|ft|-2}} but locally significantly higher, on the Southeast Asian islands of Borneo, Sumatra and Banggi.{{cite book| author1=Payne, J. | author2=C.F. Francis | year=1998 | title=A Field Guide to the Mammals of Borneo | page=243 | publisher=The Sabah Society | edition=3 | isbn=967-99947-1-6 }}{{cite web | author1=Meijaard, E. | author2=G.M. Fredriksson | author3=P. Kamminga | author4=L. Frantz | date=13 April 2018 | title=Rediscovery of a squirrel species overlooked in 177 years | url=https://www.researchgate.net/publication/324497860 | archive-url=https://web.archive.org/web/20180413190032/https://www.researchgate.net/publication/324497860_Rediscovery_of_a_Pygmy_Squirrel_After_177_Years | archive-date=13 April 2018 | url-status=dead }} Together with the African pygmy squirrel, the least pygmy squirrel is the smallest squirrel in the world, having a total length of {{cvt|10-14|cm}} and a weight of {{cvt|12-26|g}}.