The injection molding fill patterns of highly fiber filled polymer composites have sometimes been found to exhibit a leading or advanced flow front at the edges of the moldings. There is no geometric reason which can explain these advanced edge flows since flow leaders are not present in the cavity designs and cavity thicknesses are uniform. In the past, similar advanced edge flows have been demonstrated in temperature sensitive unfilled amorphous materials to be caused by shear-heating induced temperature imbalances. However, no such justification can be applied in the case of the advanced edge flow in less temperature sensitive semi-crystalline moldings – and specifically only in those which are of fiber filled polymer systems. Recent work has confirmed the influence of fiber orientation and concentration on the rheology of fiber filled polymers in rotational rheometer flows of a glass filled PA6 composite. In this present work, this rheological dependence is applied during the modelling of injection molding flows of the same PA6 composite in uniform thickness cavities where advanced edge flow has been observed by short shot moldings. In addition, measurement of fiber orientation and concentration confirm the non-uniform distribution of fiber morphology. In the flow modelling, the effects of fiber concentration depletion due to flows through the mold feed system are propagated into the mold cavity. In addition, the impact of shear stresses at the edge of the cavity are seen to influence the orientation of fibers near the part edge. These two morphology effects, combined with appropriate rheology modelling, are able to predict the occurrence of advanced edge flows.