Objective: To examine the validity and clinical utility of functional assessments (1-minute walk test, 10-meter walk test, Timed Up & Go [TUG] test, Timed Up and Down Stairs [TUDS] test, sit-to-stand [STS] test, and lateral step-up [LSU] test). Design: Cross-sectional study. Setting: Four special schools for adolescents with physical disabilities. Participants: Adolescents with spastic tetraplegia and diplegia (at levels I-III) were selected through convenience sampling (N=35; mean age, 14.97 +/- 2.03y). Interventions: Not applicable. Main Outcome Measures: GMFM-88 (dimensions D and E), 1-minute walk, 10-meter walk, TUG, TUDS, STS, and LSU tests. Data were analyzed using Pearson intercorrelations, multiple regression analysis, and multivariate analysis of variance (MANOVA). Results: Significant moderate to high intercorrelations were found. Three significant positive predictors emerged (1-minute walk, 10-meter walk, and LSU) with the following regression equation: YGMFM-88 ((dimensions D and E)) = 5.708 + .402 x X1-minute (walk) + .920 x X-LSU + .404 x X10-meter (walk) The MANOVA was significant (A = .163, F = 14.732, P<.001, eta(2) = .596), and post hoc comparisons revealed significant differences across Gross Motor Function Classification System Expanded and Revised levels in all paired comparisons for the 1-minute walk and LSU tests. For the 10-meter walk test, significant differences were evident in the level I versus level III and level II versus level III comparisons. No significant differences were found in the 10-meter walk test between levels I and II. Conclusions: These functional assessments (1-minute walk, LSU, and 10-meter walk tests) are simple to administer, quick, low cost, and user-friendly. Although these assessments are not a substitute for the criterion standard (GMFM-88), they may be used for a quick assessment in adolescents with cerebral palsy (levels I III) either at school or during rehabilitation, especially when time is limited. (C) 2014 by the American Congress of Rehabilitation Medicine