Objective: To investigate the longer-term effects of secukinumab 150 mg on fatigue in patients with ankylosing spondylitis (AS) in the MEASURE 1 study (up to 3 years) and the MEASURE 2 study (up to 2 years). Methods: Patients with active AS were randomized to secukinumab or placebo in MEASURE 1 (10 mg/kg intravenous [IV] followed by 150 mg subcutaneous) and MEASURE 2 (150 mg subcutaneous). Patients were naive to treatment with anti-tumor necrosis factor (anti-TNF-naive) therapy or had an inadequate response/intolerance to anti-TNF therapy (anti-TNF-IR). Fatigue was measured using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale. Relationships between fatigue response and baseline characteristics and clinical/laboratory variables were explored. Results: Significant improvements in FACIT-F scores from baseline were observed with secukinumab across both studies versus placebo at week 16 (P < 0.05). Improvements were sustained through week 156 (MEASURE 1) and week 104 (MEASURE 2). Significantly more patients reported fatigue responses (FACIT-F improvement ≥4; observed data) with secukinumab 150 mg than with placebo at week 16 in both MEASURE 1 (P < 0.05) and MEASURE 2 (P < 0.01). Fatigue responses were achieved by 75.6% of patients receiving secukinumab at week 156 (MEASURE 1) and 81.4% at week 104 (MEASURE 2); these results were consistent in patients who were anti-TNF-naive (74.3% and 84.6%, respectively) and anti-TNF-IR (81.3% and 75.0%, respectively). Baseline characteristics did not predict improvement in fatigue consistently. Fatigue responses were moderately to strongly correlated with responses in several clinical measures, including the Assessment of SpondyloArthritis international Society (ASAS) 20%/40% improvement, ASAS5/6 responses, the Ankylosing Spondylitis Disease Activity Score with C-reactive protein level, the Bath Ankylosing Spondylitis Disease Activity Index, and the Short Form 36 health questionnaire scores. Conclusion: Secukinumab provided rapid and sustained improvements in fatigue for up to 3 years, regardless of prior anti-TNF exposure. Trial registration: ClinicalTrials.gov NCT01358175 NCT01863732 NCT01649375.