Cell cycle arrest suppresses ferroptosis by promoting DGAT-dependent lipid droplet formation, which sequesters excessive polyunsaturated fatty acids (PUFAs) in triacylglycerols (TAGs), thereby reducing lipid peroxidation and ferroptosis. This mechanism was validated in various cell lines, including cancer cells resistant to antimitotic drugs. DGAT inhibition reshuffles PUFAs from TAGs to phospholipids, re-sensitizing arrested cells to ferroptosis. Slow-cycling, therapy-resistant cancer cells, such as 5-fluorouracil-resistant cells, exhibit increased lipid droplet accumulation and ferroptosis resistance. Combined treatment with ferroptosis inducers and DGAT inhibitors effectively suppresses the growth of such tumors by inducing ferroptosis. The study reveals that cell cycle arrest enhances lipid droplet formation, which protects cells from lipid peroxidation and ferroptosis. This finding suggests that targeting DGAT and lipid droplet formation could be a novel therapeutic strategy for treating slow-cycling, therapy-resistant cancers. The results highlight the role of lipid metabolism in regulating ferroptosis and provide insights into the mechanisms underlying cell cycle arrest-induced ferroptosis resistance.Cell cycle arrest suppresses ferroptosis by promoting DGAT-dependent lipid droplet formation, which sequesters excessive polyunsaturated fatty acids (PUFAs) in triacylglycerols (TAGs), thereby reducing lipid peroxidation and ferroptosis. This mechanism was validated in various cell lines, including cancer cells resistant to antimitotic drugs. DGAT inhibition reshuffles PUFAs from TAGs to phospholipids, re-sensitizing arrested cells to ferroptosis. Slow-cycling, therapy-resistant cancer cells, such as 5-fluorouracil-resistant cells, exhibit increased lipid droplet accumulation and ferroptosis resistance. Combined treatment with ferroptosis inducers and DGAT inhibitors effectively suppresses the growth of such tumors by inducing ferroptosis. The study reveals that cell cycle arrest enhances lipid droplet formation, which protects cells from lipid peroxidation and ferroptosis. This finding suggests that targeting DGAT and lipid droplet formation could be a novel therapeutic strategy for treating slow-cycling, therapy-resistant cancers. The results highlight the role of lipid metabolism in regulating ferroptosis and provide insights into the mechanisms underlying cell cycle arrest-induced ferroptosis resistance.