The CADIC Coalition has just completed an evaluation to document and assess the work of the CADIC Coalition campaign through the eyes of its members. In doing such an evaluation, we believe the Coalition's work will be able to contribute to future advocacy efforts and cross-sectoral campaigns for issues of social justice. The CADIC Coalition's remit, on the rights of families comprised of Irish children, their migrant parents and other close family members, has meant concentrated efforts towards win-able propositions, and their impact, and it has harnessed the unique, collective expertise, commitment and passion of a diverse group of individuals and organisations. National, regional and local NGOs, spanning human rights, legal aid, children's rights, faith-based migrant support and other migrant and immigrant support organisations came together and brought pressure on Government and State agencies to review their policies and to uphold the rights of these children and their families. As part of the evaluation of CADIC, the Coalition sought to learn about good practice in coalition building in Ireland. A process was agreed to abstract learning from the review feedback and to generalise this learning to provide a lessons-learnt document for coalition-building in Ireland. This document presents learning acquired during the CADIC review as a practical and straightforward guide to enable coalitions or those individuals and organisations that are considering building a national coalition in Ireland become more effective. This CADIC coalition-building learning document makes a number of key observations about the characteristics of a national coalition; the reasons for building a national coalition; what is useful about building and operating as a national coalition; and what are the pitfalls to be avoided when building a national coalition.