The aim of this article is to determine if the Old English verbs bewerian, forbēodan, foresacan, forwiernan, stīeran and tōcweþān constitute a unified class of prohibition. The theoretical model is provided by the framework of verb classes and alternations, as well as by Role and Reference Grammar. Class membership requires not only similar meaning components but also shared grammatical behaviour. While bewerian, forbēodan and forwyrnan are found in three syntactic configurations, and in the Nominalisation and Undergoer alternations, foresacan, stīeran and tōcweþān occur in one syntactic configuration only and do not take part in these alternations. The main conclusion of this article is that these verbs do not show a similar grammatical behaviour and, therefore, cannot be said to represent a consistent verbal class.Keywords: Old English; verb classes; alternations; Role and Reference Grammar