GAIA will measure with precision, position, velocity, and colours of tens of thousands of stars in the Magellanic Clouds and thus, will provide an important contribution to our knowledge of these two close dwarf irregular galaxies. We will consider here the impact of GAIA on the determination of the distance modulus of the LMC and the SMC, on our understanding of the global dynamics of the Magellanic system and of its star formation history. The existence of a stellar pressure-supported halo around the Magellanic Clouds can be also tested from the velocities measurements of the old stars. Moreover we show that the first generation of stars in the Magellanic Clouds could be detected from the GAIA spectra, if it could be possible to obtain spectra of stars as faint as, at least, V=17.5. A resolution of R=5000 would be sufficient for this detection.