Purpose <p>This study investigated the association between commonly used functional fitness tests (i.e., Up-and-Go Test [UGT], 30-Second Chair Stand Test [30CS], 30-Second Arm Curl Test [30AC], and 6-Minute Walk Test [6MWT]) and upper-limb isokinetc strength (elbow and shoulder flexion-extension isokinetic absolute and relative strength at 60º/s and 180º/s) in older adults. It was hypothesized that upper-limb-specific tests would show stronger associations, that elbow strength would be better explained than shoulder strength, and that higher angular velocities would demonstrate stronger associations.</p> Methods <p>Three hundred and twenty-seven apparently healthy older adults (247 women and 80 men; age: 69.27 ± 5.62) enrolled in this cross-sectional study. Isokinetic concentric strength was assessed before functional fitness tests.</p> Results <p>Small to moderate correlations were observed between functional fitness tests and shoulder and elbow isokinetic strength. Better performance in the UGT, 30AC, and 6MWT was associated with greater strength (<i>r</i> = 0.11–0.46); whereas the 30CS showed inconsistent correlations (<i>r</i> = -0.13–0.30). Regression models including functional fitness tests, age, and sex explained a substantial proportion of the variance, with higher values for elbow (<i>R</i>^<i>2</i> = 0.34–0.55) than shoulder strength (<i>R</i>^<i>2</i> = 0.12–0.42). No consistent pattern of stronger associations at higher angular velocities was identified.</p> Conclusions <p>Upper-limb isokinetic strength is associated with functional fitness in older adults, although associations were generally small to moderate. Functional fitness, together with age and sex, explained up to 55% of the variance. These findings suggest that functional fitness tests may provide indirect and complementary information related to upper-limb strength in settings where isokinetic dynamometry is not available, but they should not be considered surrogate measures of muscle strength.</p>