Traditional plant competition models have been based on population or stand level responses. These models can be considered to either reflect average population responses or to assume that individuals within the population are homogenous and uniformly spaced. Additionally, stand level modeling must explicitly account for opulation level competitive effects between plants and species. An alternative approach to modeling plant competition is the individual-based paradigm which focuses on single plants. With this technique, simulated populations are composed of individuals with unique growth characteristics and spatial arrangements. These populations can implicitly develop competitive behaviors, such as density dependent biomass accumulation, which accurately mimic real data. This paper introduces a simple individual-plant model for spring barley and wild oat competition. Models are calibrated to wild oat (Avena fatua) and spring barley (Hordeum vulgare) using data from replicated field experiments in Northern Idaho, USA.