Models for semiconductor nanocluster growth within polymer films are presented. The models assume a diffusion-aggregation mechanism of nanocluster growth, where the semiconductor molecules aggregate to form primary particles, which then aggregate, giving larger particles. Reaction-diffusion and equilibrium models based on scaling analyses have been developed. Both of the models qualitatively explain the experimentally observed effects of various processing parameters on the final nanocluster size. The models also make quantitative predictions of the variation in the final nanocluster size on varying these processing parameters. Experiments are proposed to determine whether the two models represent an accurate picture of nanocluster growth. Such models of nanocluster growth may enable a rational exploration of parameter space and guide experimentalists aiming to synthesize monodisperse semiconductor nanoclusters in polymer films.