Lesser Violetear occurs in the central highlands of Costa Rica and Panama, and south through the Andes from Venezuela to northwestern Argentina. It is present on all three Andean cordilleras in Colombia, but is very local in the Western Andes; it also is present in the Sierra Nevada de Santa Marta (Meyer de Schauensee 1949, Hilty and Brown 1986). It also occurs in the coastal ranges of Venezuela, east to northern Monagas (Hilty 2003). Lesser Violetear is present throughout the west slope of the Andes of Ecuador, south to Loja (Ridgely and Greenfield 2001), but in Peru it is present only on the east slope of the Andes (Schulenberg et al. 2010).
Lesser Violetear is not known to have latitudinal migrations, but at least in parts of its range it is not completely resident. At Monteverde, in northwestern Costa Rica, it is largely absent from June through October (Feinsinger 1974, 1976), and similarly, at one site in the Cordillera de Talamanca, Costa Rica, it is absent during the wet season (May-November) (Colwell 1973). Presumably these birds disperse to lower elevations during the nonbreeding season (Stiles and Skutch 1989). Similar elevational movements occur in Ecuador (Ridgely and Greenfield 2001), and probably elsewhere in its range. Unspecified seasonal movements are reported in Colombia (Hilty and Brown 1986) and Venezuela, where it "may disappear from some areas for months" (Hilty 2003).
The elevational range of Lesser Violetear in Costa Rica is primarily 1450-3000 m, but it descends to 1000 m after breeding (Stiles and Skutch 1989). In the Andean countries, the elevational distribution is 900-3000 m in Venezuela (Hilty 2003); mainly 1400-2200 m in Colombia, but down to 600 m on the east slope of the eastern Andes (Hilty and Brown 1986); mainly 1200-2300 m in Ecuador, but rarely down to as low as 500 m (Ridgely and Greenfield 2001); and in Peru, mostly at 1300-2800 m, but locally down to 1000 m or up to 3300 m (Schulenberg et al. 2007).