The article contributes to the scholarly debate through casting light on the (de-)securitizing character of human rights invocations by civil society organizations (CSOs) in ethno-political conflicts. The securitization concept is an innovative tool for understanding the effects of human rights activism on inter-group relationships: A securitizing move asserts an existential threat to a reference object and demands all necessary means to prevent it. Securitization reinforces the hostile 'self'-'other' conflict divide and, thus, contributes to violent escalation. Reversing securitization necessitates de-securitizing communication challenging the portrayal of the 'other' as a threat. Asking under which conditions human rights CSOs issue a securitizing or desecuritizing move, puts the interface between contextual factors, organizational behavior, and political opportunity structure at the center of interest. The empirical part examines two human rights organizations in the Zapatista conflict, highlighting the influence of the social capital from which the CSOs emerge and the applied discursive strategies.