Reactive Dye compound having formula (I) wherein: D is a chromophore group; L is a linking moiety; Q is a quaternized nitrogen derivative; X and Y are independently selected from chlorine, bromine, fluorine or hydrogen; A is selected from halogen, preferably chlorine or fluorine; provided that at least one of X and Y is fluorine; A is selected from halogen, preferably chlorine or fluorine; and salts and esters thereof. The reactive dye compounds of the invention have high Exhaustion Values, high Fixation Values, particularly on cellulosic substrates such as cotton, and show significant improvements in terms of reducing spend dyestuff in effluent, increasing dye affinity to the substrate, increasing the dye-substrate covalent bonding, increasing the ability to dye substrates at room temperature, decreasing the amount of dye that is removed during the post dyeing "soaping off process" and therefor simplying the post dyeing "soaping off process" traditionally associated with dyeing cotton with fibre reactive dyes and reduction of staining of adjacent white fabrics. In addition, the compounds prepared above provide more intense dyeings and require less levels of salt for dyeing cotton substrates.