Purpose This paper aims to account for the direct effect of ethical leadership on the sustainability of agro-allied firms and the moderating effect of environmental dynamism on ethical leadership–organisational sustainability relation. Design/methodology/approach A total of 215 managers participated in the survey, which covered agro-allied firms from the 6 geo-political zones of the country, Nigeria. Partial least square structural equation model was conducted with the aid of SmartPLSv3. Findings The result confirms that ethical leadership positively affects the sustainability of firms in the agro-allied sector and also supports that environmental dynamism strengthens the relation between ethical leadership and sustainability of firms. Originality/value The study advances ethical leadership literature through a nuanced examination of its relevance in the agricultural sector, while also validating the integrative social contract theory as a theoretical lens used in exploring the relationship. The specific focus on “ethical” leadership and a specific sector of the economy – agro allied firms is a new ground by not just looking at leadership but the ethical consideration part in relation to a specific industry where competition is a key driver to management/leadership performance.