A brake fluid pressure control system for a vehicle is provided with: a master cylinder (34) activated by the operation of a brake pedal (12); a motor cylinder device (16) that generates brake hydraulic pressure in response to an operation amount of the brake pedal (12); first brake fluid flow lines (70a, 70b) that allow the master cylinder (34) to communicate with wheel cylinders (W); two-position three-way valves (60a, 60b) arranged at connection points (S) between the first brake fluid lines (70a, 70b) and second brake fluid lines (100a, 100b). The two-position three-way valves (60a, 60b) switch between a state in which the master cylinder (34) communicates with the wheel cylinder (W) and a state in which the motor cylinder device (16) communicates with the wheel cylinder (W).