Performance of chemical resistance of weave glass fiber reel (WGFR) reinforced clay/polyester nanocomposites were fabricated to assess the influence ofmodifiedMMT (i.e.montmorillonite) clay. Research focused on two systems namely (a)polyester filled with clay and (b)reinforced withWGFR/ polyester filledwith clay are studied at different clay loadings 0, 2, 3, 5,&12 wt. % respectively. The nanoclay was dispersed by high speed mechanical shearing with the aid of the in situ polymerization.A9 vol.%ofweave glass fiber cut in to 20 mm length to prepare composites by hand lay-up method. All the samples were pre-weighed and dipped in the chemicals about 24 hrs and again weighed to find out change in %age of loss/gain of the samples. Nanocomposites exhibited good resistance to attack of all chemicals except sodium carbonate.