A complete understanding of the Universe requires us to consider matter on both the very smallest (10-18m) and largest scales (1026m). This is the realm of Particle Physics and Cosmology. We will begin by reviewing the Standard Model of Particle Physics. Following this we will look more closely at the unification of the fundamental forces of nature and the search for a grand unification theory. We will consider the important role that symmetries play in physics as well as the search for elusive particles such as the Higgs Boson. We will finish by highlighting some of the successes as well as problems of the Standard Model of Particle Physics. We will then switch our attention to Modern Cosmology and see how the observation of distant Galaxies led to the idea that the Universe is expanding. We will derive the equation of motion for the Universe and solve it for the case of a Universe dominated with matter. We will look at the evidence that leads us to believe in the Big Bang model of Cosmology and derive expressions for the size and temperature of the Universe as a function of time. Finally we will look at the evidence for dark matter and dark energy and link these back to outstanding questions in Particle Physics.