Forty patients older than 50 years with chronic Achilles tendinopathy following Haglund deformity, who did not respond to conservative treatment, were randomized to receive either debridement and ostectomy alone (control group, n=20) or debridement and ostectomy with flexor hallucis longus (FHL) tendon transfer (FHL group, n=20). The primary outcome of interest was improvement in American Orthopaedic Foot & Ankle Society (AOFAS) ankle hindfoot scores and Victorian Institute of Sports Assessment Achilles (VISA-A) scores. Secondary outcomes included surgical complications and hallux function. Outcomes were assessed preoperatively and at one-year follow-up. Overall, the results indicated that while both groups showed significant improvements in AOFAS and VISA-A scores, the FHL group demonstrated greater improvements (P < .001), though the differences did not reach the minimal clinically important difference. There were no significant differences in surgical complications or hallux function between groups. These findings suggest that while FHL transfer may enhance clinical outcomes, its additional surgical burden may not be clinically meaningful.