Cooperation between the United Nations and the private sector has intensified considerably in recent years, while the question of corporate influence has become the subject of increasing debate. This study examines the regulation of private-sector influence within the United Nations system, with particular emphasis on a comprehensive and critical analysis of the World Health Organization’s (WHO) Framework of Engagement with Non-State Actors (FENSA). It explores how the United Nations and its specialized agencies seek, through the regulatory frameworks adopted to date, to strike a balance between promoting cooperation with the private sector and safeguarding against undue influence.