The Colombian Amazon has experienced rapid forest loss in the past decades due to growing colonization, infrastructure development, and commercial agriculture expansion. While much of the analyses of deforestation in the Amazon have been in Brazil, there is a need to extend to Colombia where forest and land use exploitation are driven by post-conflict social and political dynamics. This research contributes to this knowledge gap by unpacking the mechanisms underpinning deforestation on the northwestern side of the Colombian Amazon. We used theory-building process-tracing to guide us in conceptualizing the underlying logics of deforestation in the region through qualitative text analysis of policy documents, articles, reports, and grey literature, and virtual semi-structured interviews with key national, regional and local actors. Findings indicate that the power vacuum resulting from the demobilization of FARC (Fuerzas Armadas Revolucionarias de Colombia), Marxist-Leninist guerrillas, acted as a window of opportunity for peasants, squatters, narco-traffickers, cattle ranchers, landlords, and other investors to access public lands and capitalize from converting forests to coca crops and pastures for cattle ranching. Accumulation of land and surplus primarily from cattle ranching and coca production has increased the ability of these actors to reshape the landscape and societal structures. Traditional elites and old and emerging narco-bourgeoisie have capitalized on preexisting power asymmetries by disproportionally accumulating land, money, gun power, influence, and prestige seeking to consolidate territorial hegemony, and controlling the means for material reproduction in society. Powerful actors use their resources and prestige to displace historically marginalized groups – such as indigenous communities, peasants and squatters – from their means of subsistence and production, resulting in the installation of a capitalist economy based on land rent and drug trafficking, where less powerful and marginalized actors engage in deforestation as means for capital accumulation and subsidizing their peasant and subsistence economies. All this has deepened forest loss, inequalities, and conflict over land access between actors.