Posterior spinal instrumented fusion (PSIF) is a treatment option for adolescent spinal deformity. PSIF leads to loss of spinal segment motion. It is unclear the extent to which spinal stiffness is perceived by adolescent patients after fusion. Focus groups of adolescents between ages 11 and 21 years who underwent PSIF for spinal deformity were performed. Focus groups were evaluated for common themes, and a 36-question survey was designed. Survey responses were analyzed relative to last instrumented vertebra (LIV) and Scoliosis Research Society-22 (SRS-22) scores. Five focus groups were held with 18 patients in total. Three main themes were identified by participants: 56% identified difficulty bending forward, 44% identified difficulty hunching while sitting, and 56% identified difficulty with twisting motions. Patients with more distal LIV reported significant more difficulty with self-care/grooming (P = .014) and chores (P < .001). SRS-22 function/activity scores correlated well with survey categories in self-care/grooming (r = .61; P = .049) and recreation (r = .69; P = .019). Focus groups suggest that spinal stiffness is frequently perceived and leads to alteration in daily tasks in adolescents after spinal fusion.