A soybean cultivar, designated 13873, is disclosed. The invention relates to the seeds of soybean cultivar 13873, to the plants of soybean 13873 and to methods for producing a soybean plant produced by crossing the cultivar 13873 with itself or another soybean variety. The invention further relates to hybrid soybean seeds and plants produced by crossing the cultivar 13873 with another soybean cultivar.