This study aims to establish normative values for shoulder ROM and abduction strength across different age and sex groups in healthy individuals. Both shoulders of 505 participants over 18 years of age, with no current or prior shoulder conditions, were evaluated. Measurements included ROM (flexion, abduction, external rotation, and internal rotation) and abduction strength. Participants were grouped by age (18–30, 31–45, 46–60, 61–75, over 75) and sex (male or female). A statistically significant inverse correlation was found between shoulder ROM and age (r = −0.45, p < 0.001), indicating a decline in all shoulder movements with age (abduction:​ r = −0.3738;​ flexion:​ r = −0.3866;​ external rotation:​ r = −0.4012;​ internal rotation:​ r = −0.3729;​ all p < 0.001). No significant differences in ROM were observed between sexes. Shoulder strength also decreased with age (r = −0.40, p < 0.001) and was significantly higher in men than in women (10.6 ± 3.8 kg vs. 6.0 ± 2.0 kg, p < 0.001). In conclusion, shoulder function declines physiologically with increasing age, mainly because of a decrease in internal rotation mobility and abduction strength. Also, there are clear sex-related differences in abduction strength of the shoulder which should be take into account when assessing shoulder function.