Amorphous materials lack a defined crystalline structure, exhibiting a disordered atomic arrangement that imparts superb mechanical properties and great potential for applications in many areas. Because of their disordered nature, metallic glasses exhibit dramatically different deformation behaviours than crystalline materials. A common example which stems from their heterogeneous, disordered nature is the formation of prominent shear bands. These shear bands represent narrow zones where complex strain patterns emerge due to intense shear stress. Understanding the deformation characteristics of amorphous materials remains an ongoing goal that has not yet been fully accomplished. Recent experimental observations indicate that the shear band localization is delayed or even suppressed by reducing the sample size hinting at a size-dependent phenomenon. Therefore, a size-dependent model is required to fully uncover the underlying micromechanical phenomenon. In this regard, this study focuses on the numerical modelling of disorder within amorphous materials in a contiuum setting. To this end, a lower-order strain gradient plasticity (SGP) framework is employed to numerically analyze and discuss the size effect on micro structure evolution in metallic glasses. To obtain strain patterning, two distinct approaches were utilised and compared. Shear band formations under different types of loading scenarios are modelled and analyzed. Different sized specimens are studied and compared against the classical local plasticity solutions.