In this study, upward flame spread over multiple fuel slabs is numerically studied. The fuel slab made of Poly Methyl Methacrylate (PMMA) having 1 mm thickness has been used. The parameters varied are the number of slabs and the separation distance between them. Results obtained for the burning characteristics of multiple slabs are compared with those of a single slab. The burning rate, velocity field and temperature contours are studied for each case. It is found that for a given number of slabs, when the separation distance is small, the burning rate per slab is lesser than the single slab case. When the separation distance is large enough, the burning rate becomes similar to the case of single slab. This behavior is due the nature of air entrainment and heat transfer taking place with respect to a given configuration. It is also observed that for 1 mm thick slabs, if the separation distance is 8 mm, the burning rate tends towards that of single slab case. Further, an interesting behavior is observed for separation distances of 6 mm or more, for all the cases, except for the case of 3 slabs. The flame on the outer surface of the outermost slab does not exist for these cases and only the flame is contained in the gap between the outermost and adjacent slabs. However, experimental evidence is required to validate this aspect.