This research contends that MNEs from polluting and emerging countries are subject to liabilities of origin that compel them to signal that they differ from the stereotypes of their home countries to attain environmental legitimacy. ISO 14001 adoption, which signals a commitment to environmental protection, may help MNEs from polluting and emerging countries overcome their legitimacy deficits. The wider the scope of ISO 14001 adoption, the greater its power to signal environmental awareness, and therefore, the greater its efficacy in counteracting liabilities of origin. Accordingly, this research proposes that the scope of ISO 14001 adoption by MNEs from the considered countries is wider than that of MNEs that are not subject to liabilities of origin. This contention is tested in a multisector sample of 733 MNEs over the period 2002–2019. •The scope of ISO 14001 implementation in a multinational enterprise (MNE) is a corporate-level environmental strategy.•Home-country features determine the scope to which MNEs implement ISO 14001.•ISO 14001 may help MNEs to counteract their liability of origin in the environmental field.•The scope of ISO 14001 is greater in MNEs from emerging economies and countries with poorer environmental performance.