Large companies can have both massively positive and massively negative impacts on communities, be it directly through their operations or indirectly through their influence on decision-makers. This is particularly true when business operations take place in conflict-affected or high-risk areas. Humanitarian organisations endeavouring to bring protection and/or assistance in these areas cannot, therefore, ignore these influential actors. Engagement with business actors – as well as with any other societal actor – should be framed within a clear rationale in order to deliver positive results. This article introduces the rationale that has been developed by the International Committee of the Red Cross (ICRC) and offers some examples of past engagement between the ICRC and business actors. It notes that occasions for humanitarian organisations to engage with business actors are likely to become more frequent in the coming years and argues that this trend, if properly managed, offers humanitarian organisations opportunities to leverage energies, know-how, and resources from the business sector for the benefit of the persons and communities that humanitarian organisations strive to protect and assist. Keywords: business, corporate social responsibility, community engagement, partnership, multi-stakeholder initiatives, private military and security companies, extractive industry.