Widening countries lag behind the European average in Research & Innovation investment and scientific excellence; the domain of Digital Agriculture (DA) is one prominent example. Higher Education Institutes (HEIs) of Widening countries, like Greece and Serbia, can play a central role in addressing this issue, but need support for achieving excellence in research and education in the DA domain. HEIs in Belgium have gained significant experience by establishing an ecosystem that fosters close collaboration among HEIs, competence centers, Digital Innovation Hubs, and industry, leveraging advanced digital technologies for the benefit of citizens, business, and scientific advancement. In this light, TALLHEDA will build a new long-term Alliance for DA between agricultural HEIs from Widening countries with leading non-widening agricultural universities, and local and international stakeholders. TALLHEDA Alliance will contribute to raising the critical mass of highly skilled scientists and to establishing liaisons with surrounding ecosystems, in order to foster the Quadruple Helix of innovation in Widening countries. The path to excellence will be paved with a portfolio of multi-actor, inter-sector and international complementary actions to support students, early-stage and experienced researchers, and academic staff of the Widening HEIs. This will be achieved through collaboration, complementary top-level expertise of all partners, access to cutting-edge infrastructure, staff mobility, and joint educational and research activities. The partners have an established scientific reputation in DA and are committed to making TALLHEDA a success. In the long term, Widening HEIs will be one step closer to reforming their institutions in terms of content and quality of educational courses, pedagogical and management practices, and research and innovation capacity, raising the critical mass of highly skilled scientists needed for digital transition in agriculture across Europe.