The intersection of two significant trends are affecting the regional dynamics of the Horn of Africa: the political transition underway in Ethiopia since 2018 and evolving Red Sea and Gulf security dynamics. Ethiopia’s transition has affected its relations in the Horn of Africa and the broader Red Sea region. Saudi Arabia and the United Arab Emirates have taken a much more assertive approach to regional security since 2015, contributing to a major diplomatic rift with Qatar since 2017. Elucidating how states in the Horn of Africa are affected by and responding to external influences largely hinges on understanding the Ethiopian transition. The implications for the future of regional integration in the Horn of Africa must also be considered.