Global work, by region.
US agencies buy abroad all the time: embassies, military bases, USAID and State programs. Pick a region, then a country, to see what is open there.
Open US-funded opportunities overseas
International organizations
World Bank Coming soonTenders on World Bank financed projects in 100+ countries, many open to US firms. Until it's in WARNO: World Bank procurement notices.
Source: World Bank Procurement Notices, licensed under CC BY 4.0. Modified and summarised by WARNO; the World Bank does not endorse WARNO.
United Nations Coming soonThe UN Global Marketplace lists tenders from UN agencies (UNDP, UNICEF, WFP and others). Until then: UNGM notices.
NATONATO's NSPA and NCIA buy through member nations. US firms need a declaration of eligibility from the Department of Commerce. See Europe for tenders in member states.