Objective: To test 1) if the 45-second Anterior Knee Pain Provocation Test (AKPP-test) could differentiate between adolescents with patellofemoral pain (PFP) and pain-free controls and; 2) whether improve-ments in the AKPP-test over 12 weeks were associated with improvements in self-reported knee function and pain. Design: Prospective cohort. Patients: 151 with PFP and 50 pain-free controls (age 10-14 years). Outcomes: The AKPP-test was performed at baseline, 4-and 12-week follow-up. Pain and function were collected using Knee Injury and Osteoarthritis Outcome Score (KOOS). Results: At baseline, the AKPP-test provoked pain to a median of 5 points (IQR: 3-7) on the 0-10 Numeric Pain Rating Scale in adolescents with PFP, compared to 0 (IQR 0-0) in controls. Higher pain during the AKPP-test was associated with worse KOOS-Sport/Rec (r =-0.33, P < 0.001), worse KOOS -Pain (r =-0.47, P < 0.001), and pain intensity (worst pain last 24 hours) (r =-0.39, P < 0.001) at baseline. Improvements in the AKPP-test over 12 weeks were associated with improvements in KOOS Pain (r = 0.48, P < 0.001) and KOOS Sport/Rec (r = 0.40, P < 0.001). Conclusions: Improvements in the AKPP-test were associated with improvements in self-report knee pain and limitations in sports, suggesting the AKPP-test may be a clinically responsive test of knee pain and sporting function in adolescents with PFP. (c) 2021 Elsevier Ltd. All rights reserved.