The equilibria and kinetics of complex formation between tungstate and 8-hydroxyquinoline and between both tungstate and molybdate and 8-hydroxyquinoline-5-sulphonic acid have been studied in the pH-range 7·5–9·8. Comparison is made with the reaction between molybdate and 8-hydroxyquinoline. The kinetic data, obtained by the temperature-jump relaxation technique, are discussed in terms of a detailed reaction mechanism. It is concluded that reactions of monoprotonated molybdate and tungstate ions are the main pathways for complex formation.