Fire resistant mattresses, fire resistant mattress cover materials and related methods are provided. The fire resistant mattress cover material for use as an outer layer on a mattress can include a three-dimensional knit fabric. In some embodiments, the three-dimensional knit fabric can include a first layer comprising fire resistant corespun yarns, which can be glass reinforced continuous multifilament micro denier yarns, that form a fire resistant barrier when exposed to at least one of heat or flame and a second layer comprising polymer filament yarns. The three-dimensional knit fabric can also include a middle layer between the first layer and the second layer. The middle layer can include monofilament polymer yarns knitted to provide structural support and space between the first layer and the second layer.