The purpose of this study was to examine the associations of physical, functional, experiential, and training-related characteristics with ranking in a cohort of competitive U12 tennis players. A total of 119 (boys= 68, girls= 51) nationally ranked Turkish players aged 9.6-12.3 years (10.9 +/- 0.7) were measured on stature, sitting height, body mass, skinfolds, grip strength, and agility. Age at peak height velocity (APHV), percentage of predicted adult stature (PAS%), body mass index (BMI), body fat percentages (BF%) and growth status were calculated. Weekly training hours and experiences in regular tennis training and tournament play were recorded. Compared to boys, girls were found to be significantly taller and more advanced in maturation. There were no significant relationships between growth, APHV, BMI, BF% and rankings. In girls, PAS% was significantly correlated with ranking. Results revealed that variables regarding experience, training volume, and motor performance were significantly associated with ranking in both boys and girls. Age to start regular training (r= -0.540) for the girls and weekly training volume (r= -0.489) for the boys were the most correlated variables. These results were confirmed by logistic regression models. The findings highlight the possible positive consequences of early participation in regular tennis training and tournaments, rather than growth and body composition, on the ranking of U12 tennis players in both genders.