Background/purpose: Oral exercise is a training method for swallowing dysfunction in older adults. The study investigated the effect of oral exercise on tongue pressure in older adults in Taiwanese community day care centers over a 3-month period. Materials and methods: Participants over age 50 who were able to communicate and participating for the duration of the 12-week period were recruited from five community day care centers. A 15-min weekly group oral exercise activity was conducted. The tongue pressures were measured and multivariable linear regression models were used to assess the effect of oral exercise intervention on the participants’ tongue pressures. Results: A total of 66 older adult participants, among whom the mean age was 78.06 ± 10.74 years. Tongue pressure continued improving during the intervention period, and the mean tongue pressure at the end of the study was 20.63 ± 10.45 kPa, which was significantly higher than the baseline measurement (16.92 ± 10.62 kPa, p < 0.001). Participants exhibited significant improvement in tongue pressure regardless of their age groups. Moreover, participants with one to seven pairs of functional tooth units (FTUs) exhibited significantly more improvement in tongue pressure (16.00 kPa, 95% CI = 2.58–29.43) than those without FTUs (p = 0.021). Conclusion: Oral exercise over a 3-month period significantly improved tongue pressure among the study participants regardless of their gender or age group. Oral exercise should be integrated into comprehensive health promotion programs to assist in the improvement and maintenance of oral function among older adults.