Our forward MR analysis identified suggestive associations between 7 inflammatory cytokines and thyroid cancer risks, and found that tumor necrosis factor ligand superfamily member 14 (TNFSF14) (IVW-OR: 1.25, 95% CI 1.10–1.42, p = 0.0004) is a significant risk factor in thyroid cancer, and this causal relationship remained significant after Bonferroni correction. This evidence concerns the gene TNFSF14 and thyroid cancer.