A cotton cultivar, designated DP 408 BGII, is disclosed. The invention relates to the seeds of cotton cultivar DP 408 BGII, to the plants of cotton DP 408 BGII and to methods for producing a cotton plant produced by crossing the cultivar DP 408 BGII with itself or another cotton variety. The invention further relates to hybrid cotton seeds and plants produced by crossing the cultivar DP 408 BGII with another cotton cultivar.