Lateral violence or horizontal hostility is a form of intra-group conflict where members of an oppressed group displace their aggression towards their own community rather than towards the oppressors of the community.[1] Work environments with strong vertical hierarchies and where horizontal hostility is common are associated with poor outcomes for patients and clients.[2] Horizontal hostility benefits oppressing groups and impedes movements that promote social justice.[2]

Targets of horizontal hostility may be members of the group who are perceived to be more mainstream or relatable to the oppressive cultural groups.[2]

Horizontal hostility has been studied in relation to Indigenous communities,[3] institutional settings (especially nursing),[4] and social movements such as feminism.[5]