In an attempt to understand the effects of fibre orientation on the rheology of engineering thermoplastic composites, a series of steady shear experiments were carried out on Nylon-6 composites containing short glass fibres (length <1mm) of different weight fractions: 0% (PA6), 15% (PA6-15GF) and 30% (PA6-30GF). Steady shear experiments carried out in a parallel plate rheometer showed the presence of a viscosity overshoot after which a steady state viscosity was reached for filled systems. The magnitude of the viscosity overshoot decreased as the applied shear rate was increased. The viscosity overshoot is believed to be due to the reorientation of fibres in the shearing direction as PA6-15GF samples showed a lower magnitude of viscosity overshoot and unfilled PA-6 did not exhibit any overshoot. X-Ray Computed Tomography (X-CT) was employed to measure 3-dimensional fibre orientation and local fibre concentration through the thickness direction in the fibre filled samples at a resolution of 2.5μm. An increase in the principle fibre orientation tensor (A11) value was observed as higher steady shear rates were imposed on the composite samples. Orientation tensor values were compared with predictions from Folgar-Tucker based Reduced Strain Closure (RSC) model to validate the experimental results. A MATLAB code was developed for simulating flow in a rotational rheometer to obtain the predicted values. A comparative analysis between the experimental and predicted results is then presented. By quantifying the effects of fibre alignment on rheological properties, the research work aims to develop a constitutive model that can improve Injection Moulding predictions. Keywords: Computed Tomography, Fibre orientation, Rheology, Nylon, Composites