The aim of this special issue is to widen the existing debates on security privatization by looking at how and why an increasing number of private actors beyond private military and/or security companies (PMSCs) have come to perform various security related functions. While PMSCs produce security for profit, most other private sector actors make profit by selling goods and services that were originally not connected with security in the traditional understanding of the term. However, due to the continuous introduction of new legal and technical regulations by public authorities, many non- security related private businesses nowadays have to perform at least some security functions. Little research, however, has been done thus far, both in terms of security practices of non- security related private businesses and their impact on security governance. This introduction explains how this special issue contributes to closing this glaring gap by 1) extending the conceptual and theoretical arguments in the existing body of literature; and 2) offering a range of original case studies on the specific roles of non- security related private companies of all sizes, areas of businesses, and geographic origin.