This paper analyzes frontier expansion in the Brazilian Amazon as a process that depends on multiple exogenous and endogenous factors operating at diverse scales, but whose trajectory depends on the dominant actor type (smallholders or medium- or large-scale landholders) occupying the frontier landscape. Despite the broad growing trend of pasture expansion for adoption of cattle ranching as the main land use associated with frontier expansion, some differences persist across actor types. In relative terms, medium- and large-scale landholders place most of their cleared forestland under pasture, and in absolute terms, largeholders have deforested more than smallholders because they hold larger tracts of land.Recently, however, deforestation activity has been increasing in frontiers occupied by smallholders who tend to convert a greater proportion of the forestland in their landholdings to agricultural land uses than larger-scale landholders, mainly to expand cattle ranching operations. Furthermore, smallholders tend to maintain higher cattle stocking rates than medium- and large-scale landholders, which tend to adopt extensive systems of cattle production. Both economic and human development indices in each frontier type vary according to actor type. While in absolute terms, higher per capita agricultural income levels are found in frontiers where largeholders predominate, the corresponding incomes are higher in smallholder frontiers when prorated by unit of land under crops and pasture. In addition, the Human Development Index is higher in frontiers with greater presence of large-scale landholdings.