Modern slavery and deforestation in Brazil are interconnected issues but have been approached by researchers and policy interventions separately. However, an emerging slavery-environment nexus is demonstrating the urgent necessity of engaging with slavery and deforestation holistically, to aid effective action. Accordingly, the research aimed to investigate the slavery-environment nexus in the Brazilian Amazon, by engaging with three core components: vulnerability to enslavement, slavery-deforestation links, and assessing labour and environmental inspections. Mixed qualitative methods revealed that proximate determinants of vulnerability (poverty, lack of access to land, lack of education and social isolation) are multifaceted and produced by underlying determinants (unequal land distribution, racial discrimination, economic globalisation and policies undermining distribution). Furthermore, slavery and deforestation were found to be organised by criminal networks in geographically isolated spaces, specifically among interconnected sectors at the bottom of the supply chain. These characteristics facilitate slavery and deforestation by lessening the risk of detection and punishment, which was compounded by the Bolsonaro government demobilising labour and environmental inspections. Alleviating vulnerability through redistributing land prevailed as a practical recommendation, however there is also need for research to engage further with the underlying determinants of vulnerability and slavery-deforestation links. Only then can slavery and deforestation be tackled holistically.