A design of experiments approach demonstrated how four formulation and processing factors (i.e., nanofiber type, use of dispersing agent, mixing method, and nanofiber weight fraction) affected the dynamic mechanical properties of carbon nanofiber/vinyl ester nanocomposites. Only <0.50 parts of nanofiber per hundred parts resin produced a 20% increase in the storage modulus vs. that of the neat cured resin. Statistical response surface models predicted nanocomposite storage and loss moduli as a function of the four factors and their interactions. Nanofiber type and weight fraction were the key interacting factors influencing the mean storage modulus. Nanofiber weight fraction, mixing method, and dispersing agent had coupled effects on the mean loss modulus. Employing this methodology, optimized nanocomposite properties can be predicted as a function of nanocomposite formulation and processing.