This rapid literature review provides evidence on key drivers of modern slavery. It draws on a mixture of academic and grey literature from multinational and bilateral institutions as well as non-government organisations (NGOs) and think tanks. Given the rapidly developing global context, it also draws on emerging opinion from blog posts and journalistic reports to provide evidence of current developments. Modern slavery can take many different forms, including forced labour, debt bondage, human trafficking, forced sexual exploitation, descent-based slavery, child slavery and forced and early child marriage. Slavery is considered to be a hidden and diverse crime, and understanding vulnerability to slavery remains challenging, although a consensus about the broad factors that allow modern slavery to flourish is emerging. Drivers of modern slavery rarely operate in isolation, often operating in concert, with drivers intersecting and exacerbating each other in complex ways. Evidence suggests that the following issues will likely exert an influence on the prevalence of modern slavery in a number of contexts and require a deeper level of understanding: serious and organised crime, resilience of vulnerable groups, and transparency in supply chain. When reviewing this report it is important to acknowledge that given the hidden nature of modern slavery, evidence remains mixed and patchy.