In this lecture I propose a little tour of thermal convection and itsapplications in astrophysics. The first part of the lecture is devotedto a qualitative introduction to the convective instability using theSchwarzschild criterion; then, concentrating on the equations governingthe fluid motions, I introduce the Boussinesq and anelasticapproximations which are so often used in these problems. The followingpart focuses on the Rayleigh-Bénard model which is worked out indetail up to the Landau equation and the Lorenz strange attractor.Finally, I briefly sketch out some results on turbulent convection andend the lecture with the case of stellar convection.