Flavonols have been shown to respond to a variety of abiotic stresses in plants, including cold stress. Higher total flavonoid content was found in non-heading Chinese cabbage (NHCC,Brassica campestris(syn.Brassica rapa) ssp.chinensis) after cold stress. A non-targeted metabolome analysis showed a significant increase in flavonol content, including that of quercetin and kaempferol. Here, we found that an R2R3–MYB transcription factor,BcMYB111, may play a role in this process.BcMYB111was up-regulated in response to cold treatment, with an accompanying accumulation of flavonols. Then, it was found that BcMYB111 could regulate the synthesis of flavonols by directly binding to the promoters ofBcF3HandBcFLS1. In the transgenic hairy roots of NHCC or stable transgenicArabidopsis, overexpression ofBcMYB111increased flavonol synthesis and accumulation, while these were reduced in virus-induced gene silencing lines in NHCC. After cold stress, the higher proline content and lower malondialdehyde (MDA) content showed that there was less damage in transgenicArabidopsisthan in the wild-type (WT). TheBcMYB111transgenic lines performed better in terms of antioxidant capacity because of their lower H2O2content and higher superoxide dismutase (SOD) and peroxidase (POD) enzyme activities. In addition, a key cold signaling gene, BcCBF2, could specifically bind to the DRE element and activate the expression ofBcMYB111in vitro and in vivo. The results suggested thatBcMYB111played a positive role in enhancing the flavonol synthesis and cold tolerance of NHCC. Taken together, these findings reveal that cold stress induces the accumulation of flavonols to increase tolerance via the pathway of BcCBF2–BcMYB111–BcF3H/BcFLS1 in NHCC.