Objective – To evaluate 12-week changes from baseline of 2 disease-specific patient-reported outcome (PRO) measures in adults with migraine treated with galcanezumab, an investigational humanized antibody binding calcitonin gene-related peptide (CGRP), or placebo. Background – Preventing headache-related functional impairment is an important goal of migraine preventive treatment and a measurement target for PROs. Understanding which drugs have the potential to improve patient functioning in addition to preventing migraine headaches is vital to lessening patient burden. Design/Methods – This Phase 2b double-blind, randomized, placebo-controlled study enrolled adults with episodic migraine. Galcanezumab (120 mg subcutaneous injection; n = 60) or placebo (n = 127) was administered every 28 days for 12 weeks. Post hoc secondary analyses were conducted for those who completed 12 weeks of treatment on 2 PROs: The Migraine-Specific Quality of Life Questionnaire (MSQ) v2.1 and the Headache Impact Test™ (HIT-6). Results – Analysis of covariance revealed significant differences in least square mean changes from baseline between galcanezumab and placebo for all MSQ domains including total mean change placebo of 18.63, galcanezumab of 27.36 (95% CI 2.449, 15.008; P-value of.0067); Role Function-Restrictive mean change placebo of 22.40, galcanezumab of 31.92 (95% CI 2.636, 16.518; P-value of.0071); Role Function-Preventive mean change placebo of 13.43, galcanezumab of 19.76 (95% CI 0.476, 12.185; P-value of.0342); and Emotional Function mean change placebo of 16.88, galcanezumab of 26.61 (95% CI 2.789, 16.674; P-value of.0063). At baseline, mean number of migraine headache days (MHDs) did not correlate with MSQ total scores or HIT-6. At 12 weeks post-treatment, MHD correlated with MSQ and HIT-6 scores (all P <.0001). Change in MHD was associated with change in MSQ domains and change in HIT-6 scores (all P <.0001). Conclusions – In comparison with placebo, treatment with galcanezumab was associated with significant functional improvements as reflected by changes in MSQ scores. Change in MHD was associated with improvements in MSQ and reductions in HIT-6 scores, indicating the clinical importance of these changes in relation to PROs that measure function.