A new rapid and accurate method. for the spectrophotometric microdetermination of Ga (III) ion using 7-(phenylazo) -8- hydroxy-quinoline -5- sulphonic acid and five halogen substitu- ents is given. The optimum conditions favouring the formation of the complexes are extensively investigated. The molecular structure of the complexes and their obeyence to Beer’s law, as well as, their stabilities are studied. A spectrophotometric titration method for Ga (III) with EDTA using four of these reagents as indicators is also given.