This brief summarises key considerations concerning cross-border dynamics between Tanzania and Uganda in the context of the outbreak of Ebola (Sudan Virus Disease, SVD) in Uganda. It is part of a series focusing on at-risk border areas between Uganda and four high priority neighbouring countries: Rwanda; Tanzania; Kenya and South Sudan. The current outbreak is of the Sudan strain of Ebola (SVD). SVD is used in this paper to refer to the current outbreak in East Africa, whereas outbreaks of Zaire Ebolavirus disease or general references to Ebola are referred to as EVD. The current outbreak began in Mubende, Uganda, on 19 September 2022, approximately 240km from the Uganda-Tanzania border. It has since spread to nine Ugandan districts, including two in the Kampala metropolitan area. Kampala is a transport hub, with a population over 3.6 million. While the global risk from SVD remains low according to the World Health Organization, its presence in the Ugandan capital has significantly heightened the risk to regional neighbours. At the time of writing, there had been no cases of Ebola imported from Uganda into Tanzania. This brief provides details about cross-border relations, the political and economic dynamics likely to influence these, and specific areas and actors most at risk. It is based on a rapid review of existing published and grey literature, previous ethnographic research in Tanzania, and informal discussions with colleagues from the Tanzania’s Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC), Tanzania National Institute for Medical Research (NIMR), Uganda Red Cross Society, Tanzania Red Cross Society (TRCS), International Organization for Migration (IOM), IFRC, US CDC and CDC Tanzania. The brief was developed by Shelley Lees and Mark Marchant (London School of Hygiene & Tropical Medicine) with support from Olivia Tulloch (Anthrologica) and Hugh Lamarque (University of Edinburgh). Additional review and inputs were provided by The Tanzania Red Cross and UNICEF. The brief is the responsibility of the Social Science in Humanitarian Action Platform (SSHAP).