This article is a response to an article published in this Journal by Professor Patrick Dumberry, criticising the Yukos tribunal’s conclusion that the clean hands doctrine does not constitute a general principle of law and is not a bar to an investor’s claim. Dumberry submits that strong arguments exist for considering the clean hands doctrine a general principle of law, and that tribunals, by barring claims concerning investments made contrary to host states’ laws, have been applying the doctrine. The present article contends that the Yukos tribunal is quite accurate. First, it submits that there are different forms of the clean hands doctrine, not all of which have received much support in international jurisprudence. Second, it argues that, in light of contemporary law in certain municipal legal systems, the different forms of the clean hands doctrine seemingly do not constitute general principles of law.