Background <p>Osteosarcoma (OS) is the most common primary malignant bone tumor. Recent insights into ferroptosis have opened new avenues for OS therapy. However, the role of KIAA1429 in regulating ferroptosis and its underlying mechanisms in OS remain unclear.</p> Methods <p>The effects of KIAA1429 silencing on ferroptosis were evaluated in OS cells treated with erastin alone or in combination with ferrostatin-1 (Fer-1), as well as in an OS mouse model administered sulfasalazine (SAS). Methylation sites on the Nrf2 and NQO1 transcripts were predicted using the SRAMP database and subsequently validated by MeRIP-qPCR. Furthermore, RTA-408 was employed to further investigate the impact of KIAA1429 knockdown on the Nrf2/NQO1 signaling pathway in OS cells.</p> Results <p>KIAA1429 silencing reduced cell viability and increased the expression of ferroptosis-related markers in erastin-treated OS cells, and these effects were reversed by Fer-1. Knockdown of KIAA1429 further enhanced SAS-induced ferroptosis and suppression of xenograft tumor growth. MeRIP-qPCR and dual-luciferase reporter assays demonstrated that KIAA1429 directly regulated Nrf2 via m6A-dependent modification of its 3′UTR. KIAA1429 depletion inhibited viability, migration, and invasion and promoted apoptosis of MG-63 and U2OS cells through suppression of the Nrf2/NQO1 signaling.</p> Conclusion <p>KIAA1429 silencing facilitates ferroptosis, thereby delaying OS progression, potentially through modulation of the Nrf2/NQO1 signaling pathway.</p>