Objectives: This study aimed to examine the relationship between age, body mass index, muscle strength, and balance in physically active, aged adults. Methods: Eighty-five participants were recruited for this study, having an average age of 70.31 years (SD = 9.90), ranging from 50 to 92 years. Twenty-six (30.6%) participants were male and fifty-nine (69.4%) were female. The participants had an average body mass index of 27.30 kg/m2(SD = 3.62), ranging from 20.32 to 38.58 kg/m2. Participants undertook the Timed-Up and Go to test balance, and the chair-stand test to assess lower body strength. Hierarchical regression analyses were conducted. Three models (Model 1, 2, and 3) were tested to assess their relationships with balance: M1—Lower body muscle strength; M2—Lower body muscle strength and body mass index; M3—Lower body muscle strength, body mass index, and age. Results: All hierarchical models displayed significant variance. The third model explained 50.9% of the variance in dynamic balance, [F(3, 81) = 27.94,p< 0.001, R = 0.71, Ra2= 0.51]. The difference in Ra2between the first, second, and third models was statistically significant (p< 0.05). Age, body mass index, and lower body muscle strength had significant (p< 0.05) correlations with balance. In terms of the significant impact of each predictor, age had the strongest association with balance (p< 0.05). Conclusions: The results are useful to understand mechanisms or diagnose people at risk of fall.