Background: People with epilepsy and intellectual disability should be considered at high risk of developing metabolic bone disease. Risk is increased with number of comorbidities and polypharmacy, particularly anti-seizure medications. One way of improving bone health is to ensure that every one has adequate levels of vitamin D through supplementation. Methods: This audit phase of a wider quality improvement (QI) project monitors the implementation of a Bone Health Project (BHP) for people with epilepsy and intellectual disability. Key Clinical Standard 1 of the BHP aims to ensure that where appropriate everyone prescribed anti-seizure medication is offered vitamin D supplementation. This audit standard is based upon the Scientific Advisory Committee on Nutrition Guidance. The complete audit cycle was undertaken for the entire patient cohort under the care of a specialist epilepsy service and followed QI methodology. Findings: From the initial audit, the total number of patients prescribed vitamin D supplementation increased significantly from 95 (29%) to 182 (79%) by the end of the cycle. For those prescribed enzyme-inducing anti-seizure medications, the number of patients prescribed vitamin D supplementation increased significantly from 52 (49%) to 89 (90%). Conclusions: Working collaboratively with people with intellectual disability and epilepsy can enhance engagement. Vitamin D supplementation at 800IU has been established as safe and largely efficient in ensuring most people have adequate levels of serum vitamin D. There will be people who require vitamin D replacement therapy, and this requires further intervention including monitoring of bone profiles and referral to other specialists.