Objective: To compare classification levels and trunk stabilization of wheelchair basketball players and to identify their norm values of trunk balance. Participants: 113 wheelchair basketball players in the super and first Turkish leagues. Interventions: A modified Wheelchair Skills Test (WST) (version 4.1) was used to evaluate trunk stabilization. Two skills were chosen that correspond to the stationary wheelie activity in WST, the 30-s stationary wheelie and stationary wheelie in 180 degrees. Main Outcome Measure: There are no statistical differences between WST rates and point means. Results: The skills and success and safety rates of the players with 1.5 points (51.9%, 44.4%) were lower than those of the players with 1.0 point (70%, 66.7%). In players with 2.5 and 2.0 points, the most successful and safest percentage values were 78.6%, 78.6% and 82.1%, 75%. Conclusions: Although it is expected that trunk stabilization would be better in players with high points, in our study we encountered conflicting results between the points and sitting balance or trunk stabilization. Our study supports the studies in the literature suggesting modifications in the functional-classification system.