Human society is hierarchically structured on the basic of social variables like gender. This social structuration has an influence on the uses of language. Thus, the present article deals with deontic modalities and the expression of patriarchy in Amma Darko’s Beyond the Horizon. It shows how deontic modalities, as the logic of obligation or imposition, are used by male characters to impose their domination on the female characters. As it describes and studies the qualitative properties of deontic stances, the current study relies on a descriptive qualitative method in line with Speech Acts Theory. This theory helps explain how linguistic forms are related to sense in contexts. The study reveals that, the deontic stances used by the characters in Amma Darko’s Beyond the Horizon in the contexts of obligation, prohibition and oppression reflect the ideology of patriarchy.