The effect of dispersants on particle dispersion and flexural properties of SiC/vinyl ester nanocomposites was studied by factorial and response surface designs. The results show that the coupling agent 'gamma-methacryloxy propyl trimethoxy silane (MPS)' has no adverse side effect on the flexural properties as illustrated by the good correlation between maximizing the flexural strength and minimizing the agglomerates. However, the dispersant 'BYK-W 966' has a slight adverse side effect on the flexural properties although it improves dispersion at higher dosage. With an optimal dosage of MPS and W966, a small amount of SiC in 0.5 wt% results in 8% increase in strength and 14% increase in modulus. The flushing operation using the dispersant '1-octanol/decane' achieves an excellent SiC dispersion but it does not result in improved flexural properties. This confirmed that a better state of nanoparticle dispersion does not necessarily lead to improved flexural properties. A good dispersion coupling with a strong filler/matrix interfacial bonding is the key to obtain enhanced flexural properties.