The Rusty-breasted Nunlet (Nonnula rubecula) is a species of puffbird in the Bucconidae family. It is found in two major ranges, regions of the central Amazon Basin with parts of the Guianas; the second is in southeastern Brazil, with Paraguay and Argentina, including in the interior, the cerrado. It is found in Argentina, Brazil, Colombia, Ecuador, French Guiana, Paraguay, Peru, Suriname, and Venezuela.

Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical swamps.