Advanced graduate course in theoretical particle physics. Intended for students that have completed a year of quantum field theory (at the level of PHYS 624, 851), or roughly at the level of understanding the basics of Gauge Theory, the Higgs mechanism, Loops and Renormalization. Assumes a familiarity with the Standard Model of particle physics as well as with the basics of General Relativity. Introduces the key extensions of relativistic spacetime, namely supersymmetry and extra dimensions, as well as strongly-coupled field theory and non-perturbative phenomena. Will discuss how the new physics is constrained by the host of existing precision data and LHC searches, andwill discuss its prospects for future discovery.