To date, donor strategies for aid effectiveness have focused exclusively on donor-government relationships. This paper explores whether the Paris principles also apply to CSOs. It notes that CSOs tend to adopt a human rights-based approach in assessing the effectiveness of their activities. It stresses their role as a bridge to the poor and marginalised in developing countries, and as a counterbalance to the commercial, security and political interests of donors, which can limit the policy choices available to partners. The paper argues that the creative tension in these roles is inherent to the democratic process, and should not be constrained by an artificial insistence on harmonisation. Nonetheless, the paper acknowledges that CSO practices must continue to evolve and change.