While international criminal law contains intricate rules regarding aiding and abetting, this specific body of law fails to elaborate on the ways in which one may aid or abet. This chapter first provides an overview of the relevant legal rules and the international case law regarding aiding and abetting. Next these rules are applied to funders of wars who provide financial support to a party to an armed conflict, in order to evaluate whether these funders can be held accountable as aiders and abettors. While individuals may be held responsible at the international level as aiders and abettors, companies themselves currently cannot. However, numerous individual States have enacted legislation to enable their domestic courts to determine corporate criminal liability in certain cases. This chapter therefore enquires whether domestic judicial systems can contribute effectively to the achievement of accountability when faced with cases involving companies having aided and abetted the principal perpetrator of an international crime.