Language policy prevails at different levels and its formulation typically results in a prescriptive presentation of data. In their dictionaries, lexicographers have to respond to the decisions of language policy makers. In this regard dictionaries can adhere to a strict prescriptive policy by including only the prescribed forms. Dictionaries can also give a descriptive account of language use without making any recommendations or claims of correctness. Thirdly, dictionaries can be proscriptive by recommending certain forms, even if such a recommendation goes against the prescribed forms. This article offers an overview of different levels of language policy and the principles of prescription, description and proscription. Examples are given to illustrate certain lexicographic applications of prescription. It is emphasised that access to relevant data is important to dictionary users. Consequently the lexicographic application of proscription is discussed as a viable alternative to prescription. It is suggested that proscription, in its different possible applications, can lead to a lexicographic presentation that benefits the user and that contributes to the satisfaction of the functions of a given dictionary.