Tailoring intrinsic heterogeneity and length-scale modulation is a promising approach to overcome the limited plasticity of bulk metallic glasses. One way is to introduce microstructural heterogeneities on different length-scales. This ranges from Ám-sized ductile second phase precipitates embedded in the glassy matrix down to nanometer-scale heterogeneities, which promote local shear events. Additionally, deformation-induced martensitic transformation or twinning can be exploited for plasticity enhancement. Moreover, the short and medium-range order of metallic glasses can also be tuned through mechanical pre-treatment (e.g., cold-rolling, channel-die compression, severe plastic deformation) at different temperatures. This changes the deformation behavior of inherently brittle metallic glasses remarkably, inducing a considerable increase of plastic strain via modulating internal stresses on different length-scales. The effectiveness of such treatments for ductilization will be analyzed in the light of possible structural changes and inhomogeneous stress / strain distribution.