In September 2013, two years ahead of the deadline, the Federal Ministry of Health (FMOH) and UNICEF jointly announced that Ethiopia had successfully reduced the under-5 mortality rate by two-thirds between 1990 and 2012. Ethiopia had already achieved Millennium Development Goal 4.1. In an effort to better understand Ethiopia’s remarkable achievement of MDG 4, a team of researchers, led by the Ethiopian Public Health Institute in cooperation with the Federal Ministry of Health and other partners, conducted an in-depth Countdown Country Case Study, with support from Countdown to 2015. The study’s findings, summarised in this policy brief,* provide valuable guidance on best practices and lessons learnt for other low-income countries that seek to accelerate health improvements and reduce child deaths. Based on rigorous methods for synthesizing evidence, the case study offers new insights on how Ethiopia achieved its dramatic reduction in child mortality, and examines key factors, both within and outside of the health sector, that contributed to this success. Finally, it identifies gaps and emphasises important areas where progress has been too slow and offers practical recommendations for policy and programmatic strategies to accelerate further progress.