In this presentation, we will discuss both inhomogeneous and homogeneous deformation in metallic glasses. An overview of the plastic deformation of crystalline solids with different grain sizes is first presented. In the case of inhomogeneous deformation, we examine the fundamental nature of plasticity in bulk amorphous alloys using instrumented nanoindentation technique. The mechanics of plasticity was found to depend strongly on the indentation loading rate, with low rates promoting discretization of plasticity into rapid bursts. For sufficiently slow indentations, plastic deformation was observed to become completely discretized in a series of isolated yielding events. As the loading rate is increased, a transition from discrete to continuous yielding is observed. These results are fundamentally different from the classical expectations for metallic glasses, in which the transition from discrete to continuous yielding occurs upon a decrease in deformation rate. We analyzed existing experimental results with reference to the theoretical ideal-plastic strain field beneath an indenter, and rationalized on the basis of mechanistic models of glass plasticity. In the case of homogeneous deformation (typically occurring in the supercooled liquid region), we show that Newtonian behavior is not universally observed and usually takes place only at low strain rates. At high strain rates, non-Newtonian behavior is usually observed. We demonstrate that this non-Newtonian behavior is associated with in situ crystallization of the amorphous structure.