Background Oral health worldwide needs improving: untreated dental caries is the most common health condition affecting people globally. Mobile applications (apps) have potential to provide preventative oral health interventions. This study aimed to investigate the quality of available oral health promotion apps, assessing information provided and the barriers to oral health addressed using psychological frameworks. Methods A content assessment of oral health promotion apps targeted at adults in the UK iTunes store was conducted. The quality of 22 apps was assessed against three objective indices derived from the Delivering Better Oral Health toolkit, Theoretical Domains Framework and Behaviour Change Technique Taxonomy. Index scores were calculated and descriptive analyses were completed. Results On average, four Delivering Better Oral Health messages, seven Theoretical Domains Framework components and eight Behaviour Change Technique Taxonomy components were addressed per app. The most common components were: ‘take at least two minutes to brush’ for the Delivering Better Oral Health index, ‘goals’ and ‘intentions’ for the Theoretical Domains Framework index and ‘goal setting (behaviour)’ for the Behaviour Change Technique Taxonomy index. Conclusion The quality of information available in oral health apps requires improvement with the majority addressing only a few barriers to oral health. Currently there is no recognised scale for evaluating oral health apps: this study provides a suggested method for future app evaluation. There is opportunity for a new app to be created based on health behaviour change theory which includes all the Delivering Better Oral Health messages.