The aim of this study was to examine the influence of familiarization on the reliability and construct validity of standing long jump and vertical jump in people with intellectual disability (ID). The Study included 18 students with mild to moderate levels of ID (age 2.7 + 14.1 years, Stature: 152.8 + 11.1 cm, weight: 51.1 – 17.4 kg, lower limb length: 90.1 + 14.9 cm). The examinees performed Standing long Jump (SLJ), Countermovement jump (CMJ) and free countermovement jump (FCMJ). Each Student performs 4 trials per test before and after six familiarization sessions. The results indicate no statistically significant differences between trials in FCMJ and SLJ test. As for the CMJ test, the obtained results showed that there were statistically significant differences between trial 1 and 2 and trial 2 and 3 before and after familiarization sessions, respectively. The Interclass correlation coefficient and coefficient of variation for all tests before and after familiarization sessions were higher than 0.9 and greater than 5%, respectively. The coefficient of variation was significantly reduced after familiarization ranging from 13% to 11% in CMJ test, 16.9% to 8.9% in FCMJ test, and 20.2% to 9.45% in SLJ test. Bland and Altman plots showed that the limits of agreement were 3.6 cm for the CMJ test, 3.4 cm for the FCMJ test and 1.12 cm for the SLJ test. The random error values between the 3rd and 4th trial was 1.11 cm in CMJ, 1.09 cm in FCMJ, and 1.12 cm in SLJ. The results also indicate that there were no statistically significant differences in the results of all tests between males and females. However, there were statistically significant differences between mild and moderate disability in FCMJ. We conclude from the results of this study that all jump tests appear to demonstrate good reliability and can be used for people with intellectual disabilities. As it is considered more sensitive, FCMJ is preferred for people with intellectual disabilities than CMJ and SLJ.