Diasporas are well-positioned to serve as critical advocates for their displaced countrymen. High-mobility actors with access to material and social capital, diasporic activists may seek to raise awareness, raise funds, and negotiate access for refugees from their former homeland in their new countries (Moss 2018; van Hear and Cohen 2016). Yet not all diasporas are equally successful in advancing these outcomes, and their encounters with different kinds of state institutions matter substantially (Cheran 2006; Newland 2010; Faist 2015). Based on interviews and fieldwork with Yemeni diaspora activists in the US, UK, Egypt, and the GCC states, this paper seeks to develop a typological understanding of the different kinds of barriers facing diaspora activists who advocate for refugees from their home country. We identify the effects of bureaucratic and administrative hurdles, surveillance and monitoring, restrictions on communications technology, and substantive political fragmentation within the diaspora itself as factors that inhibit the efficacy of diaspora activism on behalf of those displaced by Yemen’s war. Moreover, we explore the similarities and differences in these structural barriers in more and less open political environments, and under conditions of rapid change in several host countries. The Yemeni case stands out as significant in three possible ways, when compared with other refugee-diaspora pairings in the MENA region. First, the Yemeni diaspora has particularly longstanding ties to Egypt, the GCC, and the UK, in comparison to most other regional diasporas. We posit that intergenerational communities have resources and limitations that more recent diasporas may not. Second, structural and demographic features of Yemen’s population mean that Yemeni refugees are less able to directly self-advocate in comparison to other regional populations, and are therefore more reliant on diaspora linkages as intermediaries. And third, in comparison to other displaced populations, the blockage imposed by the Saudi-backed coalition means that Yemen also wrestles with a higher degree of internal displacement, which requires a different kind of diaspora mobilization for relief. Advocating that people be allowed to leave has some qualitative differences from advocacy on behalf of those who already have done so. Collectively, understanding the way in which diverse forms of advocacy are mobilized, received, regulated, or suppressed will move us closer to understanding how refugee advocates from outside these communities can most effectively work with diaspora activists to achieve common aims in regard to the pressing needs of refugee communities.