A rice cultivar designated CL171-AR is disclosed. The invention relates to the seeds of rice cultivar CL171-AR, to the plants of rice CL171-AR, to methods for producing a rice plant produced by crossing the cultivar CL171-AR with itself or another rice variety, and to methods for controlling weeds in the vicinity of plants of rice cultivar CL171-AR, which comprises increased resistance to acetohydroxyacid synthase-inhibiting herbicides. The invention further relates to hybrid rice seeds and plants produced by crossing the cultivar CL171-AR with another rice cultivar.