The purpose of this study was to create and assess a new series of biphenyl urea derivatives as ferroptosis-inducing anticancer agents acting through GPX4 inhibition. Thirteen compounds were rationally designed, synthesized, and evaluated for their antiproliferative activity against the NCI-58 cancer cell panel. Several derivatives exhibited pronounced growth inhibition, particularly against SNB-75 CNS cancer cells, with low micromolar IC₅₀ values. Mechanistic investigations demonstrated that the most active compounds induce cancer cell death predominantly via ferroptosis rather than apoptosis, which was strongly associated with inhibition of the important lipid peroxidation regulator; glutathione peroxidase 4 (GPX4). Notably, compound 3e emerged as a lead molecule, showing sub-micromolar GPX4 inhibitory activity (IC₅₀ = 0.27 μM) and triggering ferroptosis through increased lipid peroxidation, generation of reactive oxygen species, and depletion of intracellular glutathione. Molecular docking and molecular dynamics simulations revealed persistent binding interactions inside the GPX4 active region, supporting these findings. Overall, this study identifies biphenyl urea derivatives as promising ferroptosis-inducing leads and provides a foundation for further optimization toward GPX4-targeted anticancer strategies.