Effective altruists (EAs) have made several valuable contributions to ethical debates about international assistance. Most notably, EAs make use of evidence to produce practical guidelines for how a donor should select charities for her donations. This paper accepts the EAs’ method of ethical reasoning about international assistance from the perspective of an individual donor. However, my argument challenges the EAs’ recommendation that donors should select global charities with a narrow focus on specific projects for which there is strong evidence of effectiveness. I argue that EAs misunderstand how the donor acts to make a difference through international assistance. The donor makes a difference indirectly, by enabling and encouraging charities to act and make choices that promote good outcomes for beneficiaries. In addition, EAs overlook social scientific evidence that suggests it is often more effective for donors to grant charities discretion to use their judgment over how they choose and implement their programs. Finally, I argue that EAs should advise individuals to take action to address deficiencies in funding and public information about international assistance. EAs have good reasons to recommend action to address these problems with the institutions of international assistance, because they undermine the donor’s potential to make a difference.