Abstract: In this talk I will discuss Supersymmetric Grand Unification Theories (SUSY GUTs), focussing on the standard SU(5), SO(10) and E6 candidates. A short review of the Standard Model of Particle Physics is given as well as the main motivations for SUSY GUTs. The key features of SU(5), SO(10) and E6 representation theory are also addressed in the context of high energy physics. I will then examine the mass spectrum of the first and second generation of squarks and sleptons, providing a testable comparison of the alternative group structures. I will finally discuss how the first and second generations can be used to constrain the third generation, showing some results for the physical masses of the Higgs Bosons and third generation sfermions under the SU(5) and SO(10) symmetries.