Cochlospermum vitifolium flowers were evaluated as a raw material of natural dye on different fabrics, natural and synthetic. The dyeing process evaluation was performed by CIELa*b* color coordinates analysis. Color fastness was evaluated using the AATCC 61-1B and AATCC 116 methods. The chemical identification of the compounds in the color fraction was carried out by HPLC–MS/MS. The naringenin was determined to be the color compound. Among the natural textiles, the wool presented the best uniformity of dyeing and fixation of color, achieving the best hue when a pre-mordant treatment was used. The combination of sodium and potassium tartrate dye resulted in the best final hue, between the yellow and red regions of the CIELa*b* space (L = 49.84, a* = 5.41, b* = 45.52). The dyeing of the wool by the sodium and potassium tartrate pretreatment showed the best fastness properties to the laundering test (ΔEab = 54.56), as well as in the rub test (ΔEab = 67.36). The extract of C. vitifolium could be considered as an alternative natural dye for textiles with a protein base (e.g., wool fabrics), obtaining the best results when mordant pretreatment is used.