Economic ties between countries are likely to influence the alignment of their international policies. This paper investigates whether countries’ historical economic ties with the United States and their expectation of changes in future economic flows had a role in their decision to join the US-led coalition in Iraq from 2003 onwards. We use data on 115 countries over the period 2003–2009 to estimate panel random effects probit models of war coalition participation. We measure the intensity of economic ties with three variables: bilateral trade flows between the partner country and the US as well as FDI and aid flows from the US to the partner country. Our results suggest that both good trade relations prior to the conflict and the prospects of their further improvements increase the willingness of countries to join the coalition. In spite of the anecdotal evidence, we find no empirical evidence that the dependence on American FDI or aid affected countries’ decision on Iraq war participation.