The Purpose of this investigation was to study the effect of variability of practice and age on retention and transfer of the over-arm throwing accuracy in children. Khalajy and Shafizadeh’s (1383) test of over-arm throwing accuracy was adjusted and used in this study. 48 right-handed female children (16 children in each age group of 4, 5 and 6 years old) were selected voluntarily. Each age group was divided into the variable and constant practice groups according to their pretest scores. The variable group practiced with different target sizes whereas constant group practiced only with one target size. Acquisition phase lasted 3 days; each day included 4 blocks of 6 trials with their right hand. The collected data from acquisition phase, retention test, and immediate and delayed transfer tests were analyzed by mixed factorial ANOVA and Tukey follow-up test. The results showed no significant difference between constant and variable groups in retention test (P>0.05). But in immediate and delayed transfer tests, variable group outperformed constant group (P<0.05). The main effect of age was significant in all phases (P<0.05), so 6–year-old group outperformed 4- and 5-year-old groups but there was no significant difference between 4- and 5-year-old groups. In conclusion, the present study indicated that the age of children affected over-arm throwing accuracy but the variability of practice affected the performance of 4, 5 and 6-year-old children.