Objective: Oral health promotion resources need to be simple, useful, accessible and understandable to be effective. The importance of this is magnified for population groups who are at increased risk of poor oral health, have low literacy or language barriers. Consultation with health service providers identified the need for a readability tool to assist them to assess and develop appropriate oral health promotion resources to ensure they were written using language that was easy to understand by those with high oral health needs and low literacy levels. The objective of this study was to identify and adapt existing health literacy and readability tools and pilot the tool to determine its appropriateness for use in oral health promotion targeting those with high oral health needs and low literacy levels. Design: This paper reports the development of an oral health readability tool. Methods: Existing readability tools were identified through electronic searching and reviewed for suitability. In parallel, written oral health resources used in Australia specifically targeting refugee and asylum seeker population were identified through discussions with oral health service providers and an online grey literature search. Results: No single tool was identified which could be readily used to screen and assess written oral health resources. Two existing tools, the Fry readability formula and a suitability checklist, were therefore adapted and integrated into one tool. This new readability tool was then piloted by screening 10 written oral health resources currently in use in the public oral health sector for refugee and asylum seeker populations. Of the 10 written oral health resources assessed, only 4 were of an appropriate reading level for clients with low literacy. Conclusion: This study developed and tested an oral health readability tool to assess and develop oral health promotion resources.