This study aimed to assess the validity and reliability of jump assessments using the "MyJump2" application. Eleven junior athletes (15 ± 1.4 years) performed five countermovement (CMJ) and drop jumps (DJ) measured simultaneously by a force platform and "MyJump2." Additionally, intra- and inter-day reliability was assessed over two sessions, 7 days apart. "Extremely high" agreement between "MyJump2" and the force platform (intra-class correlation coefficient, ICC = 0.99) and the intra- and inter-operator agreement (ICC = 0.98-0.99) confirmed the validity and reliability of "MyJump2." Mean typical errors (coefficient of variation percentage, CV%) within the first and second sessions were 4.9% and 4.5% respectively for CMJs, and 8.0% to 11.8% for DJ outcomes. CMJ height held acceptable inter-day reliability (CV < 10%; ICC > 0.8), while DJ did not. Results supported "MyJump2" to be a valid and reliable tool for assessing jumps; however, with variability in DJs in this cohort, appropriate caution should be taken if including in a junior assessment battery.