This chapter reviews the current evidence relating to the facilitation of sex trafficking and, more broadly, seeks to provide a theoretical understanding of how organised crime groups and criminal networks operate in market contexts. It will begin to critically examine conceptualisations of organised crime and criminal networks, followed by a discussion of how sex trafficking fits within this. Second, it draws on situational opportunity theories of crime to explain the criminogenic milieu that shapes decision-making processes in illegitimate market contexts. Subsequently, this chapter will focus on a detailed examination of the sex trafficking crime script (Cornish DB, The Procedural Analysis of Offending and Its Relevance for Situational Prevention. In: Clarke RV (ed) Crime Prevention Studies, 2nd edn. Criminal Justice Press, New York, pp 151–196, 1994) to understand the modus operandi of traffickers and organised crime groups and, in particular, the role of technology within the three stages of sex trafficking. It concludes with the argument that whereas the role of technology in sex trafficking is variable, it does increase the number of available permutations in executing the crime script.