Aim Self‐efficacy is considered to be an important factor influencing behavior change; however, there are no existing tools to measure self‐efficacy in the context of oral health among older adults. The purpose of the present study was to develop the Geriatric Self‐Efficacy Scale for Oral Health (GSEOH) for use with older adults, and to evaluate its reliability and validity. Methods The self‐administered questionnaire was completed by 646 Japanese older people. The draft version of the scale consisted of 35 items that were generated to measure the three dimensions of personal beliefs in tooth brushing, observing own oral health status and oral function. We carried out a principal components factor analysis with promax rotation, and investigated the scale's internal consistency and construct validity. Results The final version of the scale consisted of three dimensions measured with 20 items. Cronbach's alpha of the GSEOH total scale was 0.924. There were significant differences (P < 0.05) in total scores on the GSEOH for the change process of oral health behavior, and in relation to self‐rated oral health. Conclusions We developed the GSEOH, with three factors and 20 items, and confirmed its reliability and validity. More studies are necessary to investigate the cross‐cultural validity and reliability with larger samples from other countries.