The particle theory group is active in a wide range of topics, including astrophysics, cosmology, the Standard Model, supersymmetry and string theory. The members of the group have many overlapping interests, from formal string theory to Large Hadron Collider phenomenology to particle astrophysics. While string theory is often viewed as a fundamental theory of quantum gravity, through gauge/ string duality it has also led to many breakthroughs in QCD and gauge theories. String Phenomenology aims to relate string theory and experiment by providing an underlying theory connecting the Standard Model, collider and dark matter phenomenology, neutrinos, inflation, CP violation and more. Particle astrophysics probes fundamental questions about the nature of the universe from Dark Matter and Dark Energy to inflationary cosmology and neutrino phenomenology. Particle phenomenology focuses on both the Standard Model of Particle Physics as well as physics beyond the Standard Model, such as supersymmetric grand unification and LHC signatures of new physics. The particle theory group is especially excited about the on-going experimental era, and expects to play a leading role in understanding and interpreting future possible discoveries in dark matter detectors and at the LHC at CERN. The Theory group benefits substantially from the active atmosphere provided by the Leinweber Center for Theoretical Physics which supports visitors in all areas of particle theory, and fruitful cross-connections between the particle group and astrophysics and cosmology efforts at Michigan.