The risk of chemical, biological, radiological and nuclear (CBRN) incidents has increased in recent years, due to advances in technology, and increased willingness of terrorists to use unconventional weapons. There are basic actions which can reduce or prevent harm during such incidents. The speed with which these actions can be taken may be enhanced by providing pre-incident public information about how to undertake such actions. However, limited research has been carried out to identify potential benefits of providing pre-incident information in relation to preparing for and responding to terrorist attacks, including those involving CBRN agents. This paper presents findings from a systematic literature review which aimed to: examine potential efficacy of pre-incident information campaigns for improving public preparedness for CBRN incidents; identify what information should be included within public preparedness campaigns for CBRN incidents; and identify the best method(s) of providing pre-incident information for CBRN incidents. The review was carried out using Ovid, and selection and screening of papers followed a PRISMA framework. Findings showed that providing a pre-incident educational intervention generally resulted in an improvement in preparedness, compared to not providing any information. However, the majority of studies focused on improving preparedness behaviour in the immediate or short-term (<1 month). It is therefore unclear whether any improvement in preparedness is sustainable over the medium to longer-term. Further research is required to examine to what extent public information campaigns can improve public preparedness over the longer-term, and how best to enhance preparedness for CBRN incidents specifically.