Many older adults who require long-term care need oral health management. However, access to dental care is limited, and connecting older patients with dental professionals is a future challenge. Therefore, the development of a remote oral health assessment system is required. This study aimed to investigate the usefulness of video-based oral health assessments in older adults residing in facilities. This study comprised 60 older adults residing in facilities who consented to dental home visit treatment by the Department of Oral Function Management at Showa University Dental Hospital between July 2021 and December 2022. The Oral Health Assessment Tool (OHAT) was used to evaluate the oral health status at the facilities by one dentist. The concordance of the oral health assessments conducted by this dentist at the facilities (OHAT-B) was compared with those conducted by the same dentist (OHAT-V1) and two other dentists (OHAT-V2 and V3) using approximately 1 min video recordings of the oral cavity taken with a mobile electronic device. On the OHAT total score, the intraclass correlation coefficient (ICC [1.1]) for OHAT-B and V1 was 0.931; the ICC (2.1) was 0.889 when compared with V2 and 0.788 when compared with V3. Moreover, the comparison between V2 and V3 showed high agreement, with an ICC (2.1) of 0.750. This study revealed that the oral health assessment of older adults residing in facilities using video recordings of the oral cavity taken with a mobile electronic device may be possible, suggesting the possibility of remote oral health assessment.